CHULA VISTA, Calif. (KGTV) – A young man was arrested in connection with the stabbing death of a 17-year-old boy at a Chula Vista house party, Chula Vista Police announced Tuesday.
Police said 18-year-old James Mumper Jr. was arrested at his home on Dec. 9 by the U.S. Marshals San Diego Regional Fugitive Task Force. He was booked into San Diego County Jail on suspicion of murder and assault with a deadly weapon.
Mumper was identified by CVPD investigators as the suspect in the Nov. 12 death of Mateo Castillo during a party at a home in the 900 block of Rigley Street.
Officers were called to the residence just before 1 a.m. after someone reported a person was stabbed. Police arrived to find the 17-year-old victim inside the home with a stab wound to his torso.
Castillo was pronounced dead at the scene.
Family members said Castillo was a senior at Valhalla High School and had plans to join the Marine Corps. Castillo's mother said her 15-year-old son was also at the party and tried to save his brother.
During the investigation, police learned that “a large fight began which involved multiple partygoers. During the fight, the now deceased 17-year-old victim was stabbed outside and taken into the house by others who tried to save him.”
Police said two other 17-year-old boys suffered serious injuries and were hospitalized.
Police did not release any details on what started the altercation that led to the victim’s death.
