A man has been arrested on suspicion of murder in the fatal stabbing of a 62-year-old passenger on a Gold Line train traveling through the San Gabriel Valley, authorities announced Wednesday.

The Los Angeles County Sheriff’s Department identified the suspect as 51-year-old Peter Munoz of Commerce.

He was taken into custody after investigators talked to witnesses and looked at surveillance video from the area, according to a sheriff’s news release. Authorities did not say if he is the same individual who was detained as a possible suspect in the immediate aftermath of the incident.

Munoz is accused of killing a 62-year-old man aboard a Metro train in Irwindale late Tuesday morning.

After the stabbing, the train stopped at the Gold Line station in Duarte, where the man was pronounced dead by responding paramedics, officials said. He has not yet been identified.

A weapon was recovered at the scene, but authorities did not provide further details about it.

Investigators are still trying to determine to a motive for the deadly incident, the first on a Metro train in at least three years, according to officials.

Munoz was arrested around 6 p.m. Tuesday and booked at the Temple Sheriff’s Station about five hours later, inmate records showed. He is being held without bail.

The case remains under investigation, and anyone with information is urged to call the L.A. County sheriff’s Homicide Bureau at 323-890-5500.  Anonymous tips can also be left through Crime Stoppers by dialing 800-222-8477.