RIVERSIDE, Calif. (AP) — Authorities are investigating whether a motorcycle gang rigged a Southern California police building with booby traps after becoming angry when police monitored the funeral of a member.

Hemet police spokesman Lt. Duane Wisehart said Thursday it was one of several possible motives being considered regarding the attacks.

"They are definitely one of the suspects," Wisehart said. "It's coincidental at minimum."

California Attorney General Jerry Brown and other officials announced a $200,000 reward for help finding whoever set the booby traps.

"Somebody out there is trying to kill one of our police officers," Hemet Police Chief Richard Dana said. "The only reason they haven't killed an officer yet is because we've been observant enough to see devices."

Authorities said about 30 members of the Vagos, California's largest motorcycle gang, were arrested Wednesday as part of a crackdown in Riverside and Shasta counties in California, Arizona, Nevada and Utah.

About 100 members of the Vagos gang attended the Dec. 29 funeral at a church across the street from the anti-gang unit's headquarters in Hemet, authorities said.

Officers monitored the memorial but did not attend the service. Some of the Vagos members were questioned or followed as they left town.

"They were there, we were there," said Riverside County sheriff's Capt. Walter Meyer, who oversees the regional gang task force. "Is there information that could indicate it was possibly them? Absolutely."

Meyer, however, said members of other gangs had not been ruled out as suspects.

"Obviously we have angered somebody," he said.

Two days after the Vagos funeral, someone drilled a hole in the roof of the police building and diverted a natural gas line from a heater, filling the space with flammable gas. The trap was discovered before anyone was hurt.

Last month, a contraption rigged to a security gate at the building sent a bullet whizzing past an officer's head. Nobody was hurt in that attack or another incident when an unspecified, dangerous device was found near an officer's car.

Dana said several other booby trap attacks were being investigated, but he declined to discuss details.

Meyer said there are about 200 Vagos members in Riverside County.

The gang specializes in methamphetamine sales, identity theft and violence, he said.

Hemet is located in Riverside County's San Jacinto Valley and has a population of about 75,000 people.