Once inside the door, the odor almost stopped us in our tracks. Conscious not to betray our true identities, it was more of a struggle not to betray our extreme discomfort in the face of such a foul smell.

This unlikely house call in Toronto was the latest stop in a long, relentless quest of a Jewish detective to bring Hitler's murderous helpers to justice and to help bring to light Canada's failure to first keep them out and later to deport them.

Only minutes earlier, the Holocaust had seemed light years away as we pulled up to the parking lot at 682 Warden Avenue in the Toronto suburb of Scarborough. In the building's entrance, Antanas Ceponis's name was listed on the intercom directory, exactly as it appears on page 207 of the city's 1996 phone book -- and in a list of suspected Lithuanian war criminals. On the document beside Ceponis's name the allegation stated: "Played an active role in the murder of Jews in the town of Ignalina, Lithuania."

Like many of the several thousand alleged Nazi war criminals given sanctuary in Canada after the war, Ceponis is still alive and well and living undisturbed by his past. Like almost all of them, he is virtually assured of living out his days unpunished. Unpunished perhaps, but not unexposed, due to the efforts of Steven Rambam. Since early 1994, this 39-year-old private investigator has been tracking down Nazi henchmen in Canada and, under a false cover identity, meeting with them in person. Reporters Robert Sarner and Steve Leibowitz joined Rambam separately for about a dozen of these encounters.

It's no accident that the New York-based Rambam targeted Canada to apply his investigative talents. Although Austria or Argentina would seem more fertile ground for Nazi hunting, Canada's expansive, multiethnic society - and Ottawa's longtime indifference to Nazis - has provided a near-blissful refuge for war criminals.

In their conversations with Rambam, few of the alleged war criminals come out openly and admit to having persecuted Jews. But most acknowledge they were members of notorious units which collaborated actively with the Nazis; in many countries, such activities constitute grounds for deportation.

When Ceponis opened the door of his second-floor apartment, we presented ourselves as visiting academics: Prof. Romano (Rambam) and his research assistant, Nicholas C. Papadakis (Sarner).

By now, Rambam's opening patter had become second nature and most convincing. With just the right mix of confidence and turgid, academic language, he explained that he was working on a doctoral thesis on the "interchangeability of civilian and military forces in a law-enforcement support role during wartime" and simply wanted to gather more background information for his paper.

In addition to a passport and driver's license in Romano's name, Rambam had a walletful of other ID papers to "prove" he taught at the fictitious "St.Paul's University of the Americas" in Belize for whom he was supposedly writing his thesis. Similar false ID was provided to both reporters to substantiate their cover.

In each case, Rambam conducts what is known in law enforcement as a pretext interview. The object is to get the subject to confirm his identity and then through casual conversation to unwittingly provide incriminating information - such as membership in units that collaborated with the Nazis - which can later be used as evidence against him. Under Canadian law, Rambam's actions are entirely legal.

So far, Rambam has located about 150 individuals in Canada suspected of wartime atrocities, mostly in Latvia, Lithuania and Ukraine. He has visited 60 of them, compiling a file on each. In addition, he established that several are now deceased.

Ceponis, 73, was a friendly enough fellow, ushering us in after we explained the nature of our visit; a tiny device hidden inside Rambam's sports jacket recorded every word.

We sat down in his living room, which also served as his bedroom. In addition to the pungent smell of urine and unwashed dishes, the dust-filled room was strewn with garbage. One of the few books in evidence was a hardcover copy of The Nazi Party. Taped to the wall were undated newspaper clippings in English with such headlines as "Arafat Rejects Israeli Demands" and "Zhirinovosky Spits at Jewish Demonstrators." Ceponis also kept three guns in his apartment and was delighted to show them off.

After a bit of small talk, it wasn't hard to get Ceponis to reminisce about his days as a soldier. He was a proud patriot who had willingly helped the Germans fight the Russians. He said he knew of the persecution of Jews in Lithuania but denied taking an active part in it, "except" for occasionally amusing himself by pointing a gun at Jews and making them run for their lives. "I caught Jews," he said in his heavily accented English, "and made like to shoot them but said, 'Go!' " He said he saw Jews shot in a town near Vilnius but insisted he did not shoot anyone. Later in the interview, however, he admitted having killed one Jew.

Ceponis brought out an old photo album which contained pictures of him in uniform holding a gun. To our surprise, he allowed us to take one of the pictures as illustrative material for the thesis and agreed to pose for a snapshot. We thanked him and said good-bye.

According to Yad Vashem documents, Ceponis left Lithuania for Canada on January 15, 1951, sailing aboard the Goya. During the war, he and his two brothers were known to be active collaborators with the Nazis and murderers of Jews. Their father, Victoris Ceponis, an even more notorious antisemite than his sons, was known as the Baron of Ignalina.

In the ghastly annals of Nazi atrocities, Antanas Ceponis is a minor figure. But without the participation of men like Ceponis, Hitler would never have been able to murder Jews on such a large scale. It is estimated that collectively the Nazis who came to Canada were involved in the killing of many tens of thousands of Jews, mostly in Eastern Europe.

After looking at the names and unit affiliations of those being investigated in Canada, Hebrew University historian Dov Levin pointed to the magnitude of the crimes committed by some of those on our list.

"Take Lithuania, for example, where 240,000 Jews lived at the start of the war," says Levin, a survivor of - and expert on - the Holocaust. "Some 220,000 perished, most at the hands of the Lithuanians themselves who began murdering Jews in 40 communities even before the Germans invaded in June 1941. They were organized in the LAF (Lithuanian Activist Front) and anyone wanting to prove his loyalty had to murder at least one Jew.

"Even before the invasion, they grabbed strategic points, attacked and murdered retreating Soviet troops and local Jews. Local police commanders coordinated their activities. Later, a German commander stood at the head of the hierarchy and created units of wandering murder squads who were assigned a route and timetable for eliminating Jews still alive. Typically, in each town Jews were ordered to build a trench before being shot and pushed in. By August 1941, Jews were only left alive in four ghettos."

Despite its image as one of the world's leading enlightened democracies and a haven for the downtrodden, only in recent years has Canada begun to confront its failure to pursue war criminals who entered the country with less trouble than Holocaust survivors.

"Following the war, it was easier to immigrate to Canada if you were a Nazi than if you were a Jewish survivor of the Holocaust," says Irving Abella, a prominent historian and professor at Toronto's York University whose 1982 book None Is Too Many documented for the first time Ottawa's premeditated policy of keeping Jews out of Canada before, during and after World War II. (The book takes its title from the response of a senior government official who was asked at a 1945 press conference how many Jewish refugees he felt Canada should take in from the DP camps.)

Abella says that Ottawa, like the US, was caught up in Cold War hysteria. "If you could show that you were not a communist by proving that you fought the Soviets, even alongside the German army, then that was a bonus," he says. "And we know that in order to prove that they were anti- communists and to get into Canada, some showed their SS tattoos in their left armpits. Nobody really asked whether they were war criminals. Ottawa didn't care."

With the completion of the Nuremberg Trials in 1946, Canada, like most other countries, felt there was no more need to deal with the messy business of war criminals. It was of no priority and as such Ottawa closed its eyes to the problem.

Canadian officials acknowledge the country's past policies regarding both immigration and suspected war criminals, but decline to discuss why Ottawa was indifferent for so long.

There is no definitive figure of how many Nazis were admitted but it is clear the number was substantial. The head of the Simon Wiesenthal Center in Canada, Sol Littman, says around 3,000 Nazi war criminals arrived in Canada, mostly between 1946 and 1951. Based on life-expectancy tables, he adds, close to half are still alive today.

"Many were admitted for their use to the intelligence community in the fight against communism," says Littman, speaking at the SWC's two-person Canadian office in downtown Toronto. "Some were placed here at the request of British and American intelligence services for a variety of purposes, including to help identify communists among the hordes of immigrants coming to Canada. Since then, they've been safer in Canada than in Nazi havens like Argentina and Paraguay."

For 40 years, until the mid-1980s, Ottawa officially ignored the presence of Nazi mass murderers on Canadian soil and consistently stonewalled requests by Jewish leaders to pursue the matter.

Last year, Prime Minister Jean Chretien acknowledged as much to some 1,000 Holocaust survivors at a Toronto event organized by the Canadian Society for Yad Vashem. "Too many years were lost by Canadian governments," Chretien said, "but justice must still be done."

In offering a near apology for Canada's closing its doors to Jews fleeing the Nazis, he added: "We turned our backs on Jewish refugees from Europe when we could have saved lives, when we should have saved lives. Instead, we washed our hands of the matter."

Now, however, Ottawa is up to its elbows in dealing with it, largely because of the stance taken by Justice Minister Allan Rock, whom the Jewish community says is the first minister to pursue war criminals seriously.

"The government has both a legal and moral commitment to Canadians and the international community to ensure that World War II war crimes and crimes against humanity, regardless of time and place, are addressed," Rock has said. "We will ensure that we meet our commitments in this area."

In trying to fulfill this commitment, however, the government is up against "formidable evidentiary problems" of building a solid case involving crimes committed more than half a century ago in the chaos of war, according to John Sims, the assistant deputy attorney-general. "Despite the complexity of assembling unimpeachable evidence and dealing with the courts, the government is committed to bringing Nazi war criminals to justice. I can't put a number on how many more suspects we'll bring forward, but we're urging the courts to move faster and there seems to be a stronger recognition today that time is increasingly critical in this whole program."

Sims stresses the positive when discussing the government's response to the issue. "There are few other countries in 1996 that are willing to mount a program like ours to still go after suspected Nazi war criminals."

But he refuses to criticize Ottawa's decades-long inertia before it began to take the issue seriously in the 1980s, saying it would be unproductive. "It is an inescapable fact that little happened until (that time)," he admits. "We cannot rewrite history."

Although in recent years Ottawa has attempted to make amends for its past record, it is still a source of deep bitterness for Canada's 360,000 Jews.

"The issue of Nazi war criminals has been at the top of the Canadian Jewish Congress agenda dating back to the end of World War II," says Bernie Farber, national director of community relations at the CJC, long active on the issue., "Year after year, decade after decade we had meetings with justice ministers, cabinet ministers, even prime ministers, arguing, pushing, lobbying, cajoling, begging that something be done so that the stain on Canada's historical record could be somewhat cleansed. But most of the time, we got nowhere. It was futile."

In 1987, after decades of government inaction, an official two-year inquiry chaired by Judge Jules Deschenes called for immediate legal action against 20 suspected Nazi war criminals in Canada and urged investigators to look more closely at 220 other suspects, all of whom the commission declined to identify publicly. To this day, all names remain confidential.

In 1992, as a result of a legal battle waged by Littman through the Access to Information Act, Ottawa reluctantly revealed that some 1,120 suspected Nazi war criminals were being investigated. In addition, 800 investigations had been closed due to either the person's death or insufficient evidence.

Rambam has taken a different route to uncover suspected war criminals. As an experienced private detective who specializes in undercover work and finding missing persons around the world, he is nothing if not resourceful. He also has a network of associates who have played a critical role in the operation. In their search for suspects, they consulted countless documents including driver registration lists and property ownership files. Sometimes, ironically, all they had to do was open a phone book.

Rambam received most of the names from the Wiesenthal Center and Yad Vashem. Their lists usually indicated the suspect's name, the unit he served in during the war, his date of birth and often the date and name of the ship he traveled on to Canada.

Rambam's first face-to-face encounter was with Antanas Kenstavicius, arguably the most senior war criminal still alive in Canada, who is facing deportation proceedings, based in part on evidence supplied to Canadian authorities by Rambam via an attorney. The government does not know Rambam by name.

According to historical documents and sworn affidavits from survivors, Kenstavicius was deputy chief and then chief of police in Svencionys, Lithuania, between 1941 and 1943, during which he was involved in the arrest, detention, interrogation and mass execution of thousands of civilians, especially Jews; he is accused of personally murdering three Jews. In June 1949, the CJC forwarded documents to the Royal Canadian Mounted Police (RCMP) confirming his presence in Canada. He's been living there ever since.

About a year ago, Rambam went to Hope, British Columbia, for a conversation that resonates in his memory. It took place in Kenstavicius's kitchen in the presence of his wife, Stella. During the discussion, Kenstavicius identified himself, gave details on the rounding up and killing of Jewish men, women and children, explaining how they were taken in groups of 10, relieved of all their valuables, stripped naked, shot and buried in a huge ditch. He said it took six days to kill all the Jews in Svencionys. He laughed when he talked about his men raping Jewish women.

To illustrate the impact of the meeting, Rambam played the cassette of his conversation with Kenstavicius in our car as we drove from Toronto to Montreal to meet other suspected war criminals.

Rambam played one specific portion several times. It begins with Kenstavicius and his wife, describing - in response to prodding by "Prof.Romano" - what happened after all the Jewish men had been shot dead. "Ten guys stay on ditch, and then coming the commander. Bang! And they fall down," says Kenstavicius in his heavily accented, fractured English. "Some time, repeat. Bang, bang! And they all fall in ditch. All the day. After, there're no mens. Then the womens in separate camp. Separate barracks. The kids go with the wives. First party, I look, after I no want to see. I sit there, and I no want to see. And then, zero-nine November, one o'clock, finished. No more Jews."

Rambam stops the tape and for a moment is uncharacteristically at a loss for words. "What Kenstavicius told me, and the way he says, 'No more Jews,' like it was a job well done, sent shivers up my spine." Last spring, shortly before Kenstavicius, 90, was to appear before the Federal Court on charges he misrepresented his past when he entered Canada, his wife told reporters that her husband is a sick old man who is almost blind and should be left alone.

"As a reasonable human being, I have some hesitation about prosecuting a 90-year-old man," says the SWC's Littman. "But I remind myself that he shot old men and old women without compunction. Simply because time has elapsed doesn't mean Kenstavicius is any less guilty. In his youth, he killed men who were 90 or over. His unit killed women and children."

Rambam speaks of his self-imposed assignment and is indignant that somebody else didn't do it 20 or 30 years earlier. And because so many years have elapsed since the crimes were committed, time has become Rambam's greatest enemy. The killers are dying off as are Holocaust survivors, whose testimony is essential in legal proceedings.

Zuroff acknowledges the value of Rambam's work. "There's no question that the material which Rambam has gathered and turned over to Canadian authorities will assist them in their own investigations," says Zuroff. "Confessions or confirmation of identity and unit membership will encourage Ottawa to pursue the cases."

Zuroff himself has been actively involved in finding Nazi war criminals for almost 20 years, first as an Israel- based researcher for the the US Office of Special Investigations and then as the head of the SWC's Israel office.

Zuroff - whose 1994 book, Occupation: Nazi Hunter, devoted a long chapter to Canada - helped uncover 240 cases of alleged Nazi war criminals living there. Names and other information were given to Ottawa. The suspects were primarily Latvians, Lithuanians and Ukrainians whose crimes covered the gamut of collaboration from mass murder to propaganda. The names were compiled based on various sources, in large part on documentation, research and witness testimony uncovered in Israel.

Over the past 10 years, the SWC presented numerous lists of suspects and incriminating evidence to Canadian authorities with repeated offers to cooperate in providing witnesses and further documentation, all of which were barely even acknowledged by Ottawa.

Rambam has made countless trips to Canada over the past two years, crisscrossing the country, traveling to big cities and obscure small towns in virtually every province. It is not unusual for him to drop in on several suspected Nazis in one day. In each case, he usually enters by himself equipped with a concealed listening device which records and transmits to his associate, Joey Schachter, who monitors proceedings in a nearby car and is ready to intervene if anything goes askew. He has never been attacked, although he has occasionally sensed a potential threat from family members who entered during interviews.

Since the beginning of the investigation, Rambam has not received a dime for his work. He and Schachter initially paid all costs. Several months ago, they received funding from the American-based Jeff Weltman Foundation, which supports various Jewish causes. In addition, a New York businessman who asked not to be identified has helped underwrite some of the costs.

At our hotel in Montreal, Rambam consulted his myriad files. He took out three folders, each containing a local address. With the aid of a detailed map, an itinerary was plotted entailing considerable driving from one end of the city to the other.

The first destination was the home of Juozas Lukosevicius on Carlton Street in the Hampstead neighborhood. As we approached his home, we noticed we'd entered a predominantly Jewish area with many Orthodox residents. This perverse juxtaposition did not surprise Rambam, who said he'd come across the phenomenon several times.

Last spring, for example, residents of a Toronto apartment building were horrified when they discovered that a neighbor, Konrad Kalejs, had been deported from the US a few years earlier due to his involvement in wartime atrocities in Latvia and now was the target of Canadian deportation proceedings. About half the building's tenants were Jewish, including several Holocaust survivors.

When we got to Lukosevicius's semidetached home, we were startled by the incredible sight of a mezuza on his front door. Moments after we rang the bell, his next-door neighbors -- a haredi family -- who share the same front lawn, appeared on their porch.

Lukosevicius, 81, answered the door and after initial reluctance agreed to speak briefly. He confirmed his identity and age but denied membership in a Lithuanian group collaborating with the Nazis or any other wrongdoing during the war, insisting he worked as a baker at the time. His explanations seemed forced and stilted. This from a man who, according to Soviet military records, was a member of the Lithuanian 12th Battalion of the Auxiliary Police. "Based on historical fact," says Zuroff, "it's safe to say that members of the notorious 12th Battalion were all involved in the systematic murder of Jews."

The other two suspects on the day's itinerary included one notable exception - a man who the detective came away believing was not involved in war crimes. His explanations, his manner, ambiguity in his file and the fact that he offered us the name and phone number of one of his fellow privates during the war, now living in Toronto, left Rambam 99 percent convinced that the man was innocent.

During a visit to Toronto in May, Rambam went to the home of Pranas Dovydaitas, who lives in a tall apartment building in a middle-class, partly Jewish neighborhood. He was considered a prime suspect because his crimes in Sakiai, Lithuania, are documented in Soviet history books.

Rambam entered Dovydaitas's building and found his name on the list of intercom buzzers. Schachter was waiting in a car across the street. The investigator rang upstairs, introducing himself and his "researcher." Minutes later, Dovydaitas came down to the lobby and after brief introductions, he confirmed his name and admitted that he was from the Sakiai area. He challenged the date of birth - May 13, 1924 - listed in Rambam's files which would have made him 17 when the Germans took over Lithuania in 1941. He admitted to being born on May 13, but insisted it was in 1927, making him only 14 when the atrocities occurred. He claimed that his only job during the war was digging ditches.

Dovydaitas admitted knowing about mass murders committed by Lithuanian police but emphatically denied his membership in the police or involvement in any crimes. When Rambam insisted that Dovydaitas's name was on a list of Lithuanian war criminals which was sent to the Canadian government, the old man became agitated. He confirmed he had been visited by RCMP investigators but sharply denied being aware of any suspicions against him and ended the interview.

Rambam then traveled to Niagara Falls, Ontario, about an hour's drive southwest of Toronto. One of three suspects Rambam had traced there was Kostas Stropus. The man's small dilapidated house stood on Skinner Street in what seemed to be a middle-class neighborhood. According to Rambam's file, Stropus was a rifleman in the Second Company of the 12th Battalion Auxiliary Police unit in Lithuania. Rambam knocked on his door and after exchanging introductions, Stropus led us into the living room of his messy house which he shared with a dog.

Stropus confirmed his name and birthdate, and admitted to having been a member of the unit Rambam indicated. He claimed to have never seen Jews during the war, insisting he only guarded Russian POWs in Zapyskis, Lithuania. He said the RCMP came to interview him several years back. Before Rambam left, Stropus agreed to pose for a photo.

So far, Rambam has amassed considerable first-hand evidence against dozens of suspects. "We intend to make certain that the results of our investigation not go to waste," says Rambam. "We are turning over to the authorities in Ottawa copies of interview tapes and files of those Nazis who confessed to war crimes in interviews or on whom we have built a very strong case. All the information gathered to date is already being compiled into a special investigative report to be published by the Weltman Foundation."

With each new day, the battle to bring war criminals to justice becomes more formidable. Despite the legal setbacks, judicial languor and the decreasing number of living eyewitnesses, those involved in the struggle show little weakening of resolve.

"As long as there's even one suspected Nazi war criminal still breathing in this country, it will continue to be one of the most important items on our agenda, even though it may not be so for the rest of the Jewish community in Canada," says the CJC's Bernie Farber, who has a photo on his wall of him and Simon Wiesenthal in Vienna a few years ago. "We will continue to come after them as long as they're breathing. That's the message we have to send, that the Jewish memory is a long memory, and that the Jewish quest for justice is never-ending. It's not only fidelity to justice, it's fidelity to what we are about as humankind. If we can't deal with the Nazis of yesterday, how can we effectively deal with the Nazis of today?"