Martin Mendoza was arraigned today in the San Jose Hall of Justice on charges related to the murder of Marissa DiNapoli of Morgan Hill.

He remains in the Santa Clara County Jail with no bail, following his arrival Monday in San Jose from Imperial County, where he was arrested Sunday at the U.S./Mexico border.

DiNapoli had been reported missing June 30, and her body was found near Anderson Reservoir in Morgan Hill July 2.

Mendoza, 20, was arrested by U.S. Customs and Border Protection officers while trying to cross into the U.S. at the Calexico port of entry, according to U.S. Marshals Deputy Michael Soto. The arrest of Mendoza, who was DiNapoli’s boyfriend at the time of her disappearance occurred days after Morgan Hill Police named him a person of interest in the disappearance of DiNapoli.

Morgan Hill Police Capt. Mario Ramirez said Monday that investigators “have been working tirelessly” to follow leads, dig up evidence and develop probable cause, and will continue doing so to build a murder case against Mendoza.

Local and federal investigators worked together to track and locate Mendoza at the border by July 6 to “bring him back to Santa Clara County so he can face charges of homicide,” Ramirez said.

Morgan Hill police coordinated the investigation that involved 15 law enforcement agencies, including the Santa Clara County District Attorney and Sheriff’s Offices, the FBI, the U.S. Department of Homeland Security, the U.S. Marshals Office and the Gilroy and San Jose Police Departments.

At a July 7 press conference, Ramirez declined to say when or how Mendoza crossed the border into Mexico due to the ongoing investigation.

Mendoza’s previous known location was in Morgan Hill, where he was seen with DiNapoli on June 29, at a home on Trail Drive. Home security camera footage showed DiNapoli in the company of Mendoza. The posted video clips prompted a community-wide effort to find Marissa and locate Mendoza.

Ramirez on July 7 mostly declined to offer more details of the murder investigation following Mendoza’s arrest. He said Mendoza has not provided a statement, and declined to say whether investigators think one or more additional suspects were involved in DiNapoli’s disappearance and death.

“This investigation is not done just because Mr. Mendoza is taken into custody,” Ramirez said. “We will continue to investigate, we will continue to look to uncover evidence we can provide to the District Attorney’s Office so they can prosecute Mr. Mendoza and anyone else who may have been involved.

“We’re not done. Our goal is to prosecute whoever is responsible—whether it was Mr. Mendoza or more, until they’re all held accountable for their actions.”

DiNapoli’s body was found July 2, and the coroner’s office confirmed her identity the following day. Ramirez said the medical examiner’s office has not yet determined a cause of death, or an exact time she might have died between June 29 and July 2.

Shortly after DiNapoli’s family reported her missing June 30, MHPD quickly gathered enough evidence to determine that foul play was likely a factor, and within days had assigned 30 investigators to the case from more than a dozen agencies, Ramirez said. Multiple search warrants and an arrest warrant for Mendoza were obtained by authorities in the opening days of the investigation.

Investigators tried to contact Mendoza through his known channels of communication, family members and friends, but were unsuccessful, Ramirez said. “Our only contact with Mr. Mendoza was after he was taken into custody,” Ramirez said.

Police so far have declined to share details of any of the evidence that allegedly connects Mendoza to DiNapoli’s death, due to the ongoing investigation.

Meanwhile, the grieving family of Marissa DiNapoli posted a petition on change.org calling for an investigation of the Morgan Hill Police Department and its handling of the case, accusing the department of racial bias.

“In the most critical early hours of Marissa’s disappearance, the Morgan Hill Police Department failed to respond with the urgency the situation demanded,” the petition reads.

According to the petition:

• The day after Marissa was reported missing, her sister Monicia Ramirez provided police with the exact location of Martin Mendoza Jr., the last person seen with Marissa.
• Officers confronted Mendoza in person — yet did not arrest or detain him for questioning.
• He fled within hours of that encounter.
• Days later, a community member, not the police, discovered Marissa’s body.
• Mendoza was only apprehended by accident, attempting to cross the U.S.-Mexico border a week after Marissa’s death.

“We believe this inaction was not only unacceptable — it was dangerous. We believe that racial and systemic bias played a role in the failure to act,” it said.

The petition had 3,134 signatures as of 6am Tuesday.