(KRON) — A man who investigators say recorded video of a homicide victim’s last moments alive, and uploaded the gruesome video onto his Facebook page, appeared in a San Mateo County courtroom Monday for an arraignment.

Mark Stephen Mechikoff, 39, of Pacifica, pleaded not guilty to murdering Claribel Estrella inside her San Mateo apartment on July 26. Mechikoff waived his right to a speedy preliminary hearing before he was escorted out of the Hall of Justice courtroom. He remains locked up in a Redwood City jail with no bail.

According to prosecutors, when Mechikoff stabbed Estrella to death, he felt proud of his crime, and wanted his Facebook friends to see what he had done.

“He then filmed it and posted it on his Facebook account. She was on the ground, and still alive, still moving a little bit,” District Attorney Steve Wagstaffe told KRON4.

Mark Merchikoff’s mugshot was released by the San Mateo County Sheriff’s Office.

Prosecutors added enhancements to the first-degree murder charge because of the Facebook video. “By putting it on Facebook … he felt a certain pride,” Wagstaffe said.

The veteran district attorney told KRON4, “That is the first time I’ve ever heard of anything like that. Certainly it’s never occurred in San Mateo County. It’s a horrific crime.”

Law enforcement was first alerted about the disturbing video by a woman in Florida who was Facebook friends with Mechikoff. On July 26, the woman called a sheriff’s office in Nye County, Nevada. The caller said she had just watched a video of a woman covered in blood and lying on the ground. The woman called the Nevada sheriff’s office because it was located in the last place where she knew the alleged killer lived.

Nye County deputies “pinged” a cellphone number associated to the Facebook account. Investigators tracked the cellphone’s location to a large apartment complex in San Mateo, California.

San Mateo Police Department officers swarmed the apartment complex on 37th Avenue and went door-to-door trying to find the victim. The three-hour searched ended when officers found the woman’s body.

San Mateo Police Department officers went door-to-door looking for a stabbing victim on July 26, 2023. (Image via SMPD)

“After a door-to-door search, officers found victim Claribel Estrella stabbed to death on (the) kitchen floor,” prosecutors wrote.

The killer had already slipped away from the crime scene, SMPD said. Police found Mechikoff two hours later in San Jose and arrested him.

Mechikoff and Estrella knew each other, however, prosecutors did not say how they knew each other. The victim’s friend, Cherin Knuist, said Estrella briefly dated her accused killer before she broke off the relationship, the San Mateo Daily Journal reported.

“He seemed like a bad guy, that’s why she was his ex. She mentioned he was abusive,” Knuist told the Daily Journal.

Judge Lisa Novak granted a request from defense attorneys who said they need more time to investigate the case. Mechikoff will return to court on September 15 at 1:30 p.m. to set a timeline for the case moving forward.

Although Mechikoff entered a not guilty plea on Monday, he has the option of changing his plea at future court appearances. Mechikoff’s attorneys could try to build an insanity defense.

Wagstaffe said, just because a person does something outrageous like posting a “vicious crime” on Facebook, that doesn’t necessarily mean that the person was insane.

“Doesn’t mean that they’re crazy. It’s crazy to the average citizen on the street who couldn’t conceive, would be repulsed, by doing that. But that doesn’t mean that he didn’t know what he was doing and that he didn’t intend to kill this woman,” the district attorney explained.

Investigators are still looking through evidence to establish a possible motive.