California Man Charged with Murder in Fatal Stabbing of Teen Girlfriend
A 20-year-old California man has been charged with murder for allegedly stabbing his 18-year-old girlfriend to death after confronting her about speaking with an ex-boyfriend, according to law enforcement and court documents.
Martin Mendoza Jr., of Morgan Hill, is accused of fatally stabbing Marissa DiNapoli nearly half a dozen times and leaving her body near Anderson Lake in Santa Clara County. He was arrested after allegedly attempting to flee to Mexico following the killing, the Santa Clara County District Attorney’s Office said.
Surveillance footage and cellphone data provided a timeline of the tragic events. On June 29, Ring security cameras captured Mendoza and DiNapoli leaving a Morgan Hill residence around 9:45 a.m. The criminal complaint reveals that Mendoza was visibly confronting DiNapoli as they walked downstairs, with her expression showing apprehension.
Shortly after leaving the residence, Marissa’s cellphone was tracked traveling east toward Anderson Lake. Both her phone and Mendoza’s pinged in the area between 9:58 and 10:04 a.m. By approximately 10:14 a.m., the phones were moving away from the lake, but Marissa’s device showed its final activity around 10:18 a.m., authorities said.
DiNapoli failed to appear for her shift at Starbucks later that day, alarming coworkers who told police she was dependable and usually worked the afternoon shift. A missing person report was filed on June 30.
On July 1, Mendoza’s vehicle was captured by surveillance cameras as he tried to cross the U.S.-Mexico border at San Ysidro. DiNapoli’s body was discovered on July 2 near Anderson Lake, suffering from five stab wounds to her back.
Authorities arrested Mendoza when he attempted to return to the U.S. on July 6. Investigators later learned from DiNapoli’s family that she had suffered multiple previous incidents of domestic violence at Mendoza’s hands, although those incidents reportedly went unreported to law enforcement.
Mendoza was arraigned on Tuesday, facing charges of murder committed with the use of a deadly weapon and multiple aggravating circumstances, including inflicting great bodily injury, targeting a vulnerable victim, and abusing a position of trust. He remains in custody without bond and did not enter a plea during his initial court appearance.
Santa Clara County District Attorney Jeff Rosen condemned the violence, stating, “This is a tragic example of the deadly consequences of intimate partner violence. We will seek justice for Marissa and her loved ones.”
Marissa’s death has sparked renewed calls for awareness and intervention in abusive relationships, as local authorities emphasize the importance of seeking help in situations involving domestic violence.
The case remains under investigation as prosecutors prepare to pursue charges that could result in a life sentence for Mendoza if convicted.
