cuffs, handcuffs
Photo credit: Alexander Nguyen

 An 18-year-old man has been arrested in the murder of a 17-year-old boy at a Chula Vista house party, authorities said Tuesday.

The U.S. Marshals San Diego Regional Fugitive Task Force arrested James Mumper Jr. of San Diego at about 4:45 p.m. Friday for the murder of Mateo Castillo, according to the Chula Vista Police Department.

Police received a 911 call around 12:45 a.m. on Nov. 12 reporting that someone had been stabbed and was dying in the 900 block of Rigley Street, according to the CVPD.

Officers responded less than five minutes later and found Castillo with at least one stab wound to the upper body and performed life-saving measures until fire department personnel arrived and relieved them, according to authorities.

Fire and medical staff continued life-saving measures in the home, but the victim was pronounced dead just after 1:30 a.m.

In addition to the 17-year-old victim, officers found an unconscious 17-year-old male in front of the house with serious injuries to his face and upper body. Witnesses told police he had been assaulted by several people during a fight. He was taken to a hospital for treatment and was listed in stable condition, police said.

Officers also found another 17-year-old male about two blocks away at East Palomar Street and Medical Center Court who had a stab wound to his upper body. It was determined that his wound was related to the same incident, police reported. He was taken to a hospital and was listed in stable condition.

The homeowner was believed to have been present during the party and remained on the scene to cooperate with officials.

The victims’ names are being withheld due to their ages and the active investigation, the CVPD reported.

County jail records indicate Mumper is being held without bail on suspicion of murder and assault with a deadly weapon. A spokeswoman for the San Diego County District Attorney’s Office said Mumper would be arraigned Tuesday afternoon.

Authorities are still seeking public help to identify additional suspects. Anyone with information about the incident is asked to contact San Diego County Crime Stoppers at 888-580-8477.

Updated at 11 a.m. Dec. 13, 2022

–City News Service