Not one, but five independent witnesses recounted the tale, recalling how they rushed to a German army camp, borrowed weapons and gunned down 500 Jews inside the town's Christian cemetery. One of them remembered decapitating bodies in front of the church.
The man heading the research that led to this discovery discussed it in Israel last week; Father Patrick Desbois was in Pope Benedict XVI's entourage.
Desbois is a French Roman Catholic priest. His team has been investigating mass executions in the former Soviet Union during the Holocaust for more than six years. In 2004, he founded Yahad-In Unum, a Paris-based organization devoted to Christian-Jewish understanding.
Oral testimonies from these events in Ukraine and Belarus are but a part of Desbois' research. Using metal detectors, his team uncovers German-made cartridges and bullets as well as victims' jewelry from killing pits. The findings are transferred to an archive in Paris, where the testimonies are translated.
Earlier this year, Desbois helped start the first Holocaust masters program at the Sorbonne, focusing on the extermination in the former Soviet Union.
To Desbois, there are two holocausts: a western one and an eastern one. The western holocaust was more organized, whereas the eastern one, "the one that happened away from Berlin," was chaotic, decentralized and undocumented.
"German officers wanted to appear efficient, so they documented one mass grave and declared the place judenfrei. In reality, the killings went on for years," he says. "The only way of documenting these [other] graves is asking the locals. Time's running out, and we're the only organization on the ground there."
The Ternopil story is not unusual because of its extreme cruelty but because it's so rare for perpetrators to openly admit playing a voluntary role. Most stories Desbois hears are from people who claim that the Germans forced them to take part in executions. "[Securing testimony from five participants in] a pogrom is a historic achievement," Desbois told Haaretz.
He notes how "we couldn't have achieved this a few years ago. We didn't have the skill." He says his team's success reflects the ability to keep a poker face.
"If I react with shock, it's all over," he explains. "Often I don't react at all to what the witnesses say. I just give them an interested expression and ask very technical questions about where they stood, where the victims lay, the time of day. I keep them talking and it pours out."
Desbois' full-time, nine-member team includes a cameraman who films the testimonies, while the others listen to stories of murder and human degradation.
But sometimes the poker face cracks, he says. For instance, when one woman described how her mother would "finish off" wounded Jews with a shovel blow to the head before burying them. "My team started to react, so I kept her talking, asking in a matter-of-fact way how exactly her mother would administer the blows."
Often with local help, the Germans killed nearly 1.5 million Jews in Ukraine after their invasion of the Soviet Union in 1941. Most of that history has gone untold. Unlike in Poland, where Jews were killed in death camps, in the Soviet Union most were mowed down and dumped into open mass graves in woodlands.
"I understand those who ask if Ukrainians and Poles were willing allies in the extermination of Jews," he says. "But I don't ask myself that, since most people I interview were children at the time. I'm only concerned with reconstructing the crime and knowing where the bodies are."
Desbois says one of his most surprising discoveries is institutionalized sexual slavery. In several interviews, he found witnesses who said German soldiers would set up houses in ghettos where they raped Jewish women. The Germans and their accomplices usually executed the women near the end of the war.
This discovery challenged perceptions that ideologically-motivated Germans would not sexually exploit a member of what the Nazis termed an inferior race.
Such accomplishments landed Desbois an honorary doctorate last week from Bar-Ilan University.
He says he arrives at a small town with five researchers and an interpreter. One approaches elderly people, who often lead the team to unmarked mass graves.
He began working in Ukraine in 2002, when he traveled to the village of Rava-Ruska. He went there in the footsteps of his paternal grandfather, who was deported to a prison camp for French soldiers.
Having researched the fate of French prisoners, Desbois discovered that 10,000 Jews had been killed at Rava-Ruska, but the town's mayor said he knew nothing.
So far, Desbois' organization has interviewed nearly 1,000 witnesses. His team has dug up mass graves only in one locale, at the request of the French Jewish community: "We do not uncover graves because of Jewish religious restrictions."
For the witnesses, the return to the killing ground is often the first time back in decades. "There, they recall more details," Desbois says. "Where the Germans stood, where this or that family was gunned down, a woman who couldn't walk and was dragged to the killing pit, or a woman who wouldn't take her clothes off."
Debois says easterners are more eager to talk about the Holocaust than westerners. "People in Ukraine want to talk. They wait on benches to be interviewed and filmed. They take us to grave sites, they welcome us into their homes - homes that used to belong to Jews," he says. "Imagine what would happen if I went around churches in Munich asking people if they helped kill Jews?"
Not another John Paul II
According to Father Patrick Desbois, the disappointment with the pope's speech at Yad Vashem -which officials at the memorial authority described as "lacking compassion" and "too general" - stems from a misunderstanding of the Holy See.
"People were expecting another Pope John Paul II. But Benedict is very different," Desbois says. After teaching mathematics as a French government employee in West Africa and working in Calcutta for three months with Mother Teresa, Desbois joined the priesthood. His secular family was horrified.
When he first began researching the extermination of Jews in the former Soviet Union, he preferred to keep it a secret for a long time. "A priest, a goy, a Catholic who does what I do.... I was afraid people would call me a fool," he says.