CAMPBELL (CBS SF) — A Los Gatos man was charged earlier this week with possession of assault weapons, multiple silencers, drugs and the makings of a pipe bomb after Campbell police found him prowling outside of a business and discovered the arsenal and a racist manifesto detailing a shooting plot in his vehicle.

32-year-old Los Gatos resident Wesley Charles Martines was arraigned on multiple felonies Tuesday in the Hall of Justice. A judge remanded him on $300,000 bail.

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According to the Santa Clara District Attorney’s Office, bullets inscribed with such phrases as “Cop Killer,” along with a handwritten manifesto saying he wanted to wipe out the Black, Hispanic and Jewish populations were found in his vehicle.

Just after midnight last Friday, July 9, Farukh Mamedov, owner of Revv Auto Sales at 60 E. Sunnyoaks Avenue in Campbell, called Campbell police to report a man seen on a security camera app, prowling in the used car lot, who was looking into cars and a storage shed.

“So the guy came in, he lifted up the cover off the car, and then he went out back and started searching for things, he’s kind of just prowling around,” said Mamedov.

Officers responded to the scene, but Martines had left. Officers spotted the truck a short time later, and stopped Martines.

“So his demeanor throughout the interaction, I would describe as calm. He was not confrontational with us. However, on our initial approach during the traffic stop, the fill-in officer observed one of the AR-15 style assault rifles out in the passenger seat,” said Campbell Police Captain Ian White.

Inside the vehicle, they found the weapons, including two AR-style rifles, which are illegal in California. Officers also found a Glock 9 mm handgun and ammunition that was personally inscribed with such sayings as “Cop Killer,” “To a widow from the Grim Reaper” and “A Good Start.” Police additionally discovered body armor, heroin, methamphetamine and a pipe bomb filled with pellets, but no explosive material inside.

“Great reporting by a witness, and a really heads up spot by our officers. A great stop and great investigation. Lives were saved. Inevitably lives were saved,” said White.

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“Good thing I was up, I was able to call it in. Think we prevented a tragedy from happening,” said Mamedov.

The Santa Clara County Sheriff’s Office Bomb Squad assisted in making sure the explosive device was inactive.

A journal found by authorities contained racist and anti-Semitic writings, along with details of a plan to go to a sporting goods store dressed as an employee and tie everybody up.

With assistance from the DA’s Office, Campbell Police obtained high bail, search warrants and served a gun violence restraining order (GVRO) on the suspect to seize his weapons.

“This resident is a hero for contacting the police. Campbell police did an outstanding job by responding immediately, and stopping this guy,” said Santa Clara County District Attorney Jeff Rosen.

Rosen noted that investigators were still trying to determine a motive behind what Martines was apparently planning.

“We don’t know at this point, what was driving this person to have these thoughts, and to want to commit these terrible crimes. We’ll hold him accountable, and hopefully get him the help that he needs if, if that’s appropriate,” said Rosen.

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If convicted, Martines faces up to 5 years and 4 months in prison. His next court appearance is July 21.