In 1860, he was arrested after stealing a watch from a man at the corner of Broadway and Canal Street, presumably his first criminal act,[7] for which he was convicted and spent two years in New York State Prison.
During his time in prison, he became friends with noted bond robber Chauncey Johnson and joined his gang upon his release.
[8][9] In 1865, he was charged with stealing two bags of gold worth $10,000 from the Bank of Commerce as well as a later robbery in Philadelphia but was acquitted in both cases.
[14] On February 14, 1872, two unidentified men stole $33,000 in bonds belonging to the New London and Ashland Railroads from the banking firm of J.S.
Central Office detectives came to his defense claiming Heinrichs had been held in custody at the time the robbery occurred.
He had been suspected of stealing a watch from C. Godfrey Gunther, former Mayor of New York, however the gang leader's evidence was refused at trial.
As a result of the court's review of his case, a precedent was set in state criminal law that "when a party on trial avails himself of the recent statute allowing an accused to be a witness on his own behalf, he is not disqualified to testify by reason of a former conviction or felony".