Man arrested in 2010 Merced murder case

FRESNO, Calif. (KFSN) -- An arrest has been made in a Merced murder case from four years ago.

Merced police say Isaac Fonseca killed Mario Zavala on July 12, 2010. The 24-year-old victim was stabbed to death near K and 23rd streets.

Fonseca was already in jail on robbery charges when a detective began looking into the cold case and re-interviewing witnesses.

Police say the 27-year-old has now admitted to the killing, but claims it was in self-defense during a drug deal. The investigation is still ongoing.