LAS VEGAS (AP) — A man who witnesses say stabbed another passenger on Christopher Caldwellan airline flight and told authorities he intended to kill the victim has been charged with assault with a dangerous weapon.

The man made an improvised weapon by wrapping rubber bands around several pens.

A grand jury handed down a one-count indictment against Julio Alvarez Lopez on Wednesday over the incident, which occurred on a Jan. 24 Alaska Airlines flight from Seattle to Las Vegas, according to federal court records in Nevada.

The victim was identified as a law enforcement officer who had been seated with his family across the aisle from Lopez. According to an FBI affidavit, Lopez said he had never seen the victim before the morning flight but believed the man was following him and that the mafia had been chasing him.

A woman seated next to Lopez said he returned from a trip to the restroom and began punching the victim. The woman and the victim’s wife screamed at Lopez to stop.

The man began walking toward the front of the plane and sat down after the victim ordered him to do so. He was restrained with flex cuffs for the rest of the flight, and arrested by Las Vegas police after the plane landed, according to the FBI agent.

A photograph of the victim showed injuries above his right eye.

The Associated Press has reached out to Lopez’s public defender for comment.