New York City Mayor Eric Adams reveals gunman Shane Tamura acquired part of his rifle from an associate on 'The Story.'

The gunman who killed an NYPD officer and three other people in a Midtown building on Monday evening was carrying a note that offered clues into his possible motive, sources told The Post.

A second note was found at his home in Las Vegas, investigators shared July 29. The news comes after another letter was found earlier in which the suspect wondered about “CTE,” chronic traumatic encephalopathy,