Police are searching for a suspect after a man was found stabbed to death on a train in Long Beach Wednesday.

The victim was only described as an adult male in his 20s, by Long Beach police.

Officers responded to reports of a stabbing on the Metro Blue Line on the 100 block of East 1st Street around 3:38 p.m.

When authorities arrived, they found an adult male victim “suffering from apparent stab wounds to the body.”

Detectives determined the victim boarded the train outside of Long Beach and “sometime after the Metro Rail entered Long Beach, three unknown male suspects boarded, immediately approached the victim, and began physically assaulting him.”

During the assault, one of the suspects stabbed the victim multiple times which resulted in his death, police said.

When the train came to a stop near 1st Street and Pine Avenue, the suspects exited and fled on foot before officers arrived.

The victim was transported to a local hospital where he was pronounced dead, police confirm.

The motive behind the stabbing remains under investigation, but police say the incident “does not appear to be random.”

This incident marks the third reported stabbing on a Metro line within a week — including stabbings at the Hollywood Western and Westlake/MacArthur stations.

Detectives are searching for additional witnesses on the Long Beach stabbing and any cell phone video that may show the suspects.

Anyone with information is asked to contact Homicide Detectives Donald Collier or Chasen Contreras at 562-570-7244. Anonymous tips can be submitted through “LA Crime Stoppers” at 800-222-8477 or online at lacrimestoppers.org.