Morgan Hill, California – A 20-year-old man, Martin Mendoza Jr., has been charged with murder after allegedly killing his 18-year-old girlfriend, Marissa DiNapoli, last week. Authorities say Mendoza confronted DiNapoli about talking to her ex-boyfriend, leading to a violent altercation. Security footage shows the moments leading up to the murder, where Mendoza stabbed her in the back nearly five times before leaving her to die at Anderson Lake.
The Incident
The Santa Clara County District Attorney’s Office shared details about the events leading to DiNapoli’s death. On June 29, Mendoza and DiNapoli were seen together on Ring camera footage leaving a residence in Morgan Hill. The footage shows Mendoza confronting DiNapoli about contacting her ex-boyfriend, and DiNapoli’s facial expression is described as visibly apprehensive during the confrontation.
Later that morning, both of their cellphones showed they were heading toward Anderson Lake. According to authorities, Mendoza’s vehicle was also seen traveling west on E. Dunne Avenue near Heritage Green Park at 10:14 a.m. – around the time DiNapoli’s phone last showed activity.
Discovery of the Crime
DiNapoli failed to show up for her shift at Starbucks on June 30, and her co-workers confirmed she was almost always on time for her PM shift. This prompted a missing person report to be filed. Mendoza’s vehicle was captured on surveillance video attempting to cross into Mexico on July 1, just days after the murder.
DiNapoli’s body was found July 2 at Anderson Lake, with five stab wounds to her back. The investigation revealed previous incidents of domestic violence between Mendoza and DiNapoli, though these had not been reported.
Arrest and Charges
Mendoza was arrested on July 6 when he attempted to return to the U.S. from Mexico. He was charged with murder committed with a deadly weapon and other aggravated circumstances, including great bodily injury (GBI), using a weapon, and exploiting a position of trust. He was held without bond and did not enter a plea during his arraignment.
