After Polish investigators reopened an active search for Nazi war criminals, they discovered Schuster, who was now living in East Germany.

He was deployed to Belarus with the task of fighting guerrillas, shooting Jews whom he had helped select.

After a failed attempt by partisans to destroy his post, Schuster moved to the St. Catherine monastery, believing Poles would be less likely to shoot at a church.

[1] When carrying out a village "pacification", Schuster would have the population chased into one area and then have his men read out a list of names.

[4][5] In 1967, a Polish war crimes commission, led by Andrzej Jankowski, conducted an investigation into Schuster.

In 1969, Jankowski informed East German officials about Schuster, prompting the Stasi to cease contact with him.

As an officer of the fascist gendarmerie and leader of a motorized train, he organized, ordered and carried out the arrests, ill-treatment and shooting of women, children and men in occupied areas during the Second World War."

[6][7][8] Jankowski was allowed to participate in Schuster's interrogation and provided assistance to Polish witnesses questioned by the local prosecutor's office.

At one point during his trial, Wacław Dziuba, a surviving witness, said he had been saved by an unexpected act of mercy by one of Schuster's men.

"[10][11] The presiding judge responded by mentioning the name of one of Schuster's victims, Wanda Piwowarczyk.

Piwowarczyk was a two-year-old girl whom Schuster had personally executed as she was crying and hugging her mother.

Schuster waited for Piwowarczyk's mother to recover from the shock of watching her daughter being murdered, then smiled at the woman and shot her in the head.

He was found guilty of participating in the rounding and deportation of Jews in the Belarusian town of Novogrudok and murdering of at least 400 villagers in Poland, and sentenced to death.