The former 'bookkeeper' of Auschwitz described in court today the grisly killings he had witnessed at the death camp as a 21-year-old SS Guard working as a clerk.
Oskar Groning, now 93, told the Lueneburg court he witnessed in 1942 Jews being herded into a converted farm house near the camp.
An officer shut the door, put on a gas mask, opened a can and poured its contents down a hatch, he said.
"The screams became louder and more desperate but after a short time they became quieter again," Groning said.
"This is the only time I participated in a gassing," he added, before correcting himself: "I don't mean participated, I mean observed."
He also said on his first day he witnessed an SS colleague grab a crying baby and slam its head against a truck until it was quiet.
"I was so shaken," Groning said, adding that at the time he told a superior: "I don't find what he did good at all."
He later asked his commander for a transfer from Auschwitz.
Although not directly responsible for killing anyone at the death camp, he is charged for being accessory to at least 300,000 Jews who were sent to the gas chambers between May and July 1944, the indictment says.