The governor of the U.S. state of Rhode Island has pardoned an Irish immigrant who was hanged more than 150 years ago following what is believed to be a tainted a murder trial.

Governor Lincoln Chafee signed the order Wednesday pardoning John Gordon, who was convicted of killing the brother of a U.S. senator and hanged in 1845.

Historians say the evidence against Gordon was circumstantial and the trial was tainted by bigotry against Irish Catholics.

Chafee said Wednesday “there is no question” Gordon was not given a fair trial, and that the pardon is an attempt to “right that injustice.”

He also said the execution was a major factor in the state abolishing the death penalty. Gordon was the last person to be executed in the state, which banned the punishment in 1984.

The governor signed the pardon in Rhode Island's Old State House, the site of Gordon's trial.