Harry Wentritt was a mechanic at the motor pool administration of Germany’s Security Police, which was Subdepartment II D 3a of Germany’s Department of Homeland Security (Reichssicherheitshauptamt). In 1966, together with his superior Friedrich Pradel, he stood trial for allegedly having made mechanical changes to a set of trucks in 1941/42, turning them into homicidal gas vans. He should have been the one person perfectly able to describe exactly how these vehicles functioned and what type of engine they used.
However, in all his statements, he said nothing about the type of engine used (gasoline or diesel). When it comes to the way the exhaust gases were introduced into the cargo box, he described a technically absurd and nonfunctional method: He claimed that a piece from the van’s exhaust pipe was cut out, and a T-piece inserted instead. This was then used to attach a metal hose to an opening cut into the cargo box’s floor.
A truck’s exhaust pipe does not extend all the way to the back of the truck but usually ends half way on one side. Connecting it to a hole in the center of the cargo box would certainly be possible with a metal hose, but inserting a T-piece makes no sense at all. Any exhaust pipe ends in the open. If it is too long, simply cut it short. Otherwise, connect it to the opening in question as needed. There is no point in cutting a piece out from the middle of the pipe, then reconnect the trailing end of it with a T-piece. Furthermore, a simple T-piece would have foiled the purpose of redirecting the gas, because the gas, following the path of least resistance, would have escaped from the tailpipe into the open rather than flowing into the enclosed cargo box. Piping the gas into the box would have required the closure of the other exit of the T-piece. But since this trailing end of the exhaust pipe was not needed, the entire exercise is futile. A simple elbow pipe redirecting the end of the exhaust pipe toward the opening in the floor would have done the trick.
Two other witnesses have made similarly foolish statements years before Wentritt. Maybe Wentritt learned this nonsense from reading their accounts. (See the entries on Bronisław Falborski and Johann Hassler.)
Wentritt ended up serving three years for his alleged contribution to the creation of the gas vans. It was deemed served with the time he had spent in pre-trial detention. Hence, he walked away as a free man.
(For more details, see Alvarez 2023, pp. 211-219.)