This is the original marginal story that I tried to research further on its own: C.A. Barr and his amazing machine.
The Pinkerton Detective Agency was hired by the L.Q.White company after a botched robbery of its payroll on Christmas Eve (this robbery attempt was the prequel to the Braintree Robbery). They began to follow a dapper man who either claimed to know who the bandits were or was one of them. He later was overheard saying that the would-be bandits were Italian Anarchists.
The Pinkerton detectives along with Chief Stewart of the Bridgewater Police (the man who eventually set the trap that caught Sacco and Vanzetti) finally caught up with the dapper man. He stated his name was C.A.Barr (originally Barosso, an Italian) and that he had invented a machine
"with which he could detect who had committed a crime no matter where it was committed."
He stated that one Mrs. Vetilia had looked into the machine and saw the [attempted Bridgewater] holdup happening and saw the men plainly but did not know who they were.
BUT it is very interesting that someone planted early on into Chief Stewart's head that "it was a group of Italian Anarchists." No matter how ridiculous the story is, it could have had a material, practical effect of subtly slanting Chief Stewart's investigation.
I refer to the handmade Opaque projector used at the beginning of the show as
C.A.Barr's Miraculous machine.