SAN JOSE, Calif. — A man whose home has been the site of a dayslong police search by bomb squad technicians, hazmat teams and federal agents is now charged with a series of felonies alleging he bombed two PG&E electrical transformers in South San Jose at the turn of the new year, according to court documents.
One of the damaged transformers was in front of the Macy’s department store at Westfield Oakridge Mall.
A criminal complaint filed Friday by the Santa Clara County district attorney’s office details nine charges against 36-year-old Peter Karasev, 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.
Karasev, who was arrested Wednesday, also was charged with three counts of felony child endangerment because he is accused of conducting bomb-making activities with his three young children living in the same home.
After his arrest, a large contingent of police officers and bomb techs — later joined by explosives specialists with the FBI and the National Guard — began a methodical warrant search of Karasev’s home on Potomac Court, about a block north of Gunderson High School across Chynoweth Avenue.
According to a police investigative summary accompanying the criminal complaint, San Jose police were called in the early morning hours of Jan. 5 to the intersection of Snell Avenue and Santa Teresa Boulevard after a ground-based transformer exploded and caused damage to surrounding buildings. That included a dental office whose windows were blown out.
The ensuing investigation revealed that PG&E had a similar transformer explosion Dec. 8 on Thornwood Drive, in front of the Oakridge Macy’s.
A combination of surveillance video, including from a parked Tesla, and cellphone ping tracking were used by police to pinpoint who was in the areas during these early-morning incidents. That search led them to suspect Karasev, according to the police summary.
One of the key pieces of surveillance video evidence was footage showing a person riding a bicycle toward the Jan. 5 alleged bombing site — a strip mall in the southwest corner of Snell and Santa Teresa — a few minutes before the 2:52 a.m. explosion. That footage showed the person leaving a backpack next to the transformer and biking away, followed by the blast.
PG&E workers reportedly told investigators that had the transformer experienced some kind of malfunction, the presence of mineral oil would be apparent and that it would more likely heat up and catch fire rather than explode. They also said that “the damage was in an inward direction,” and “believed the cause was from an external explosive device.”
With the Dec. 8 transformer explosion on the Oakridge Mall grounds, it was initially thought of as a malfunction after PG&E responded to a power outage in the area.
Both transformer explosions occurred between 1:45 a.m. and 3 a.m. on their respective dates, and the similarities between the two instances — with the general location, time and method — led San Jose detectives to suspect that one person was responsible for both.
The cellphone tracking found one device was present at and around both scenes, and a cell-service warrant revealed to detectives that Karasev was associated with the overlap.
Police determined that Karasev worked at Zoox, a Foster City-based subsidiary of Amazon that works on autonomous vehicles. Detectives surveilled and tracked Karasev at work and home for a couple of weeks prior to his March 1 arrest.
The investigative summary also stated that a warrant return for Karasev’s web search history showed that minutes after the Dec. 8 explosion, he was looking up the terms “san jose news,” “shaped charge,” and was looking up electrical outages on PG&E’s website. A shaped charge is part of an explosive meant to direct the blast in a specific direction.
Two weeks ago, San Jose police were contacted by an FBI agent reporting that Karasev had purchased online a series of chemicals related to producing meth. To this point, he has not been charged with any drug-related offenses.
Detectives summarized a post-arrest interview with Karasev in the criminal case file, in which he reportedly told interrogators that he thought he had been arrested because he had been testing out model rockets, as one explanation for his alleged possession of explosive materials. He also described an academic background that included a doctorate in computer science and aerospace engineering.
The investigative summary also includes a narrative of a police interview with a woman identifying as the mother of Karasev’s three children. She reportedly confirmed that he would go on late-night bicycle rides.
Detectives would later write in the summary that among the items recovered in the home search this past week was a mountain bike that shared similar features with the one recorded on surveillance near the Jan. 5 explosion.
A precise motive has not been disclosed by investigators. Karasev was scheduled to be arraigned on the criminal charges Friday afternoon in a San Jose courtroom.
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