A Pomona man pleaded guilty Friday to second-degree murder for shooting a man after an argument at a Long Beach party and was immediately sentenced to 25 years to life in state prison.

Thearath Sam, 30, also admitted that he personally used a firearm in the killing of Sambo Chhoy, 33, on January 20, 2014, according to the Los Angeles County District Attorney’s Office.

Sam was at a party in Long Beach when he got into an argument with the victim, according to Deputy District Attorney Hubert Yun.

Arrest Made in Murder of Sambo Chhoy, Gunned Down on MLK Jr. Day

The two men went into a back alley after being told to leave the party, and Sam followed Chhoy for two blocks before shooting him, the prosecutor said.

Shortly after the shooting, Long Beach police said they responded to the area of New York Street and Martin Luther King Jr. Avenue about a report of shots fired when they discovered Chhoy, a Long Beach resident, with a gunshot wound. He was pronounced dead after being taken to a hospital, police said.

 Sam was arrested the following month by Long Beach police, according to jail records.