A person of interest in the murder of UnitedHealthcare CEO Brian Thompson was arrested in Altoona, Pennsylvania, Monday, sources told the New York Post.

The man was arrested after police received a tip called in from a McDonald’s in Altoona, a five-hour drive from where the shooting took place in Manhattan. When apprehending the suspect, police uncovered a gun, silencer, four fake IDs, and additional items that are consistent with the suspect they have been seeking. The man also allegedly had a manifesto on him when he was taken into custody, the Post reported.

The real identity of the suspect is still unknown.

Thompson was shot just before 7 a.m. on Wednesday in a "brazen targeted attack" outside a Midtown hotel where his company was holding an investors meeting. Thompson’s killer escaped on an electric Citi Bike, investigators said. The NYPD announced Friday that the suspect had likely fled New York City.

Police said Thompson’s shooter was "lying in wait" for several minutes before he gunned down the CEO. "Many people passed the suspect, but he appeared to wait for his intended target," officials added.

The motive of the execution is still unclear, but the killer’s bullets found at the scene appeared to have the words "deny," "depose," and "defend" written on them, a message that mirrors the title of a book that denounces the health care insurance industry, the Post reported.

Thompson’s wife said on Wednesday that her husband had been receiving threats before he was killed.