An active-duty U.S. Air Force sergeant suspected of wielding a rifle and improvised explosives in the ambush killing of a 38-year-old Northern California sheriff’s deputy is also being investigated for a possible connection to the fatal shooting last month of a federal officer during a protest in Oakland, multiple sources told ABC News on Sunday.

The suspect, Steven Carrillo, 32, was taken into custody on Saturday after he was wounded in a shootout with law enforcement officers in the Santa Cruz Mountains, about 35 miles west of San Jose, officials said.

Carrillo is alleged to have fatally shot Sgt. Damon Gutzwiller and injured another deputy when he attacked them with a rifle and multiple improvised explosives in Ben Lomond, California, authorities said. A California Highway Patrol officer was also wounded during a shootout that erupted as officers moved to take Carrillo into custody, officials said.

“In my 32-year career, this is my worst day I’ve ever experienced,” Santa Cruz County Sheriff Jim Hart said at a news conference on Saturday evening. “Today we lost one of our own and he was a true hero.”

Carrillo is an active-duty sergeant assigned to the 60th Security Forces Squadron based at Travis Air Force Base in Fairfield, California, about 100 miles northeast of Ben Lomond, 2nd Lt. Mike Longoria, a spokesman for the base, told ABC News on Sunday. Longoria referred all other questions about Carrillo to the Santa Cruz County Sheriff’s Office.

Multiple law enforcement sources told ABC News that the FBI is investigating a possible link between the deadly ambush in Santa Cruz County and the May 29 killing of Federal Protective Services Officer Dave Patrick Underwood in Oakland.

Underwood, 53, was guarding the Ronald V. Dellums Federal Building during protests that broke out in the Bay Area city over the police-involved killing of George Floyd in Minneapolis, Minnesota, when he was shot to death while standing outside the building, officials said.

A white cargo van that appeared to not have license plates was spotted racing from the scene of Underwood’s slaying, according to the FBI, who released security photos of the vehicle last week. The FBI warned that the “occupants of the van should be considered armed and dangerous.”

The deadly attack on Saturday unfolded after a caller contacted a 911 dispatcher at 1:30 p.m. to report seeing guns and bomb-making material inside a suspicious van parked off the road in the Santa Cruz Mountains, Hart said.

Gutzwiller and other sheriff’s deputies arrived at the scene just as the van was pulling away. They followed the van to a house in Ben Lomond and as they approached the vehicle gunfire rang out.

“As deputies began investigating, they were ambushed with gunfire and multiple improvised explosives,” Hart said.

Another deputy was either shot or struck by bomb shrapnel and was hit by a vehicle as the suspect drove out of the driveway of the home, he said.

Within minutes after the attack, 911 dispatchers received multiple calls from people reporting a carjacking nearby and officers from police agencies throughout Santa Cruz County raced to the scene, according to Hart.

He said Carrillo was arrested after being shot and wounded. He said a California Highway Patrol officer was also shot in the hand during the ordeal.

Carrillo was taken to a local hospital where he was treated and released to the custody of sheriff’s deputies.

The FBI and the Santa Cruz District Attorney’s Office are investigating the incident.

Hart said Carillo was arrested on charges of murder, assault with a deadly weapon, carjacking “and a myriad of other charges.”

“There’s a lot that we don’t know at this point. It’s still a very fluid situation,” Hart said. “I ask that the community be patient as we go through this investigation and the grieving process.”

Hart said Gutzwiller’s colleagues were planning to hold a vigil for him in front of the Santa Cruz County Sheriff’s Office headquarters on Sunday at 2:36 p.m. PST, the time the call came on Saturday that an officer was down.

He said Gutzwiller, who joined the sheriff’s office in 2006, is survived by a young child and a pregnant wife.

The sheriff described Gutzwiller as a “beloved figure” who started his career in law enforcement as a volunteer with the sheriff’s office.

“In this era that we’re in, when you think about what you want to see in a police officer, compassion, caring, somebody who truly loves his job, who wants to help people, that’s what Damon was,” Hart said. “He was a good man and a good police officer.”

California Gov. Gavin Newsom and his wife, Jennifer, released a statement expressing their shock and dismay over the killing of Gutzwiller.

“Jennifer and I extend our heartfelt condolences to the family, friends and coworkers of Santa Cruz County Sheriff’s Sergeant Damon Gutzwiller, who was tragically killed while on duty,” the governor’s statement reads. “He will be remembered as a hero who devoted his life to protecting the community and as a loving husband and father.”

An Air Force spokesperson said Carrillo arrived at Travis Air Force Base in June 2018 and was a team leader on the Phoenix Raven unit. That group is comprised of “specially trained security forces personnel dedicated to providing security for Air Mobility Command aircraft transiting high terrorist and criminal threat areas,” according to an Air Force website.