San Jose PG&E transformer bombing case search turns up dangerous material

A search of the home of a man charged last week with bombing two PG&E electrical transformers in South San Jose over a one-month span yielded a hoard of dangerous materials capable of producing a "serious tragedy," according to city officials.

Peter Karasev, 36, has been charged with nine felonies, according to a criminal complaint filed Friday by the Santa Clara County District Attorney's Office, including two counts of igniting a destructive device, one count of arson, two counts of interfering with electrical lines, and a count of possessing bomb-making materials. Police say Karasev planted homemade explosives near electrical transformers on Dec. 8 and Jan. 5, knocking out power to more than 1,000 customers.

One of the explosives damaged a transformer outside of the Macy's at Westfield Oakridge Mall, which struck a personal chord with Mayor Matt Mahan, who was among the authorities speaking at a Wednesday news conference at San Jose poilice headquarters.

"Our (police) department and its partners have averted what likely could have been a serious tragedy," he said. "Oakridge Mall was mentioned, that's where my wife and I take our little kids sometimes. So you can just imagine, had our department not done the incredible work they’ve done, what could have potentially played out here."

Assistant police Chief Paul Joseph said that over the course of a four-day search at the Potomac Court home that ended Saturday authorities found large quantities of hazardous materials, including "homemade liquid explosive, multiple energetic homemade destructive devices and multiple suspected destructive devices," as well as materials used to construct explosives. Authorities said at least five firearms were also recovered during the search, which was joined by the FBI.

The charges filed Friday against Karasev also included child endangerment, as Karasev's three young children resided at the home with him and his wife. Neighbors in the adjacent homes were displaced during the search, which took place about a block north of Gunderson High School in South San Jose.

"As far as the ongoing danger, it was huge," Sgt. Doug Gates said. "The amount of potential material that we found within the location, (which could) either cause a fire or cause an explosion (affecting) the entire community, including a school that was across the street, was large."

Authorities screened surveillance video from the Jan. 5 bombing, which showed a man riding away on a bicycle as smoke began to emit from a nearby transformer. The department also displayed photos of the firearms found at Karasev's residence, as well as what looked to be homemade pipe bombs.

Joseph said investigators still don't know the motive behind the alleged attacks. He added that he was unaware of any plans for more bombings when Karasev was arrested March 1.

The bombed transformers were "in a relatively close proximity to each other, relatively close proximity to his home, and I don't know if that was out of convenience or some greater plan in his mind," Joseph said.

He added that Karasev is highly educated in science fields, but it was unknown if that formed the basis of his presumed knowledge of bomb-making. A LinkedIn page connected to Karasev describes him as having a master's degree in electrical and computer engineering and a doctorate in computer engineering from Georgia Tech.

Karasev most recently worked at Foster City-based electric robot-minibus company Zoox, a subsidiary of Amazon, as a senior engineer in machine learning.

Zoox issued a statement late Friday in response to an inquiry from the Bay Area News Group about Karasev's arrest, confirming he has been working there since last August. Officials added that the company "is cooperating fully with the police and conducting its own investigation."

"Safety is foundational at Zoox," the statement reads. "Mr. Karasev is currently on leave. As this is an ongoing investigation, we cannot comment further on the accusations."

Staff writer Robert Salonga contributed to this report.

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