A disturbing incident has shocked California, as a 20-year-old man has been charged with the murder of his 18-year-old girlfriend, Marissa DiNapoli. The victim’s tragic death followed an argument about her communicating with an ex-boyfriend.
Security footage and cellphone data helped authorities piece together the chilling details of the crime.
The Incident Unfolds
On June 29, 2025, Martin Mendoza Jr., 20, was seen in a Ring camera video leaving a residence in Morgan Hill with his girlfriend, Marissa DiNapoli. This was just one day before Marissa went missing and two days before her body was discovered at Anderson Lake on July 2.
According to the Santa Clara County District Attorney’s Office, the video showed the couple walking down the stairs together. As they walked, Mendoza was seen confronting Marissa about contacting her ex-boyfriend, and Marissa appeared visibly uncomfortable.
The Final Moments
Cellphone data revealed the couple’s movements after they left the residence. They were last seen traveling toward Anderson Lake around 9:52 a.m. on June 29. Cellphones showed their phones in the area between 9:58 and 10:04 a.m., and later traveling away from the lake at around 10:14 a.m.
The timeline suggests that shortly after, Marissa’s phone stopped showing activity.
Marissa did not show up for her shift at Starbucks that day, which was unusual since she typically worked the evening shift. This led her coworkers to report her missing on June 30. Meanwhile, Mendoza was captured attempting to cross into Mexico on July 1, but his return to the U.S. on July 6 led to his arrest.
The Murder Discovery
The investigation soon revealed the horrific details of Marissa’s death. Her body was discovered at Anderson Lake with five stab wounds to her back.
Authorities also uncovered a history of domestic violence incidents between Mendoza and DiNapoli, which had gone unreported. Marissa’s family members shared that there had been multiple prior incidents of physical abuse.
Legal Proceedings
Martin Mendoza Jr. has been charged with murder, with the use of a deadly weapon, and with aggravating circumstances. These include great bodily injury (GBI), being armed, and targeting a vulnerable victim.
Mendoza has been denied bond and has yet to enter a plea. His case has highlighted the devastating effects of domestic violence and the tragic end of a young life.
The case of Marissa DiNapoli’s death is a reminder of the dangers of abusive relationships. With Mendoza now facing serious charges, the case will continue to unfold in court. For now, her family and friends are left to mourn the loss of a promising young woman whose life was taken too soon.
The investigation into this case underscores the importance of recognizing signs of abuse and seeking help before it leads to such tragic consequences.
