Sonoma County Issues Condolences in Wake of Marin Deputy's Fatal Shooting

Sonoma County Assistant Sheriff Lorenzo Duenas offered condolences Tuesday afternoon to Marin County Sheriff's Department and the family of Marin County Sheriff's while trying to help a friend.

"Sonoma County Sheriff Steve Freitas and our whole department send our condolences to Marin County Sheriff's Department and the family," Duenas said in a news conference at the Sonoma County Sheriff's headquarters in Santa Rosa.

"Jim Mathiesen was doing what his career had taught him to do, which is helping people," Duenas said. "Unfortunately, he got caught in the crossfire, and he paid the ultimate price."

Duenas declined to release the names of the occupants of the Petaluma home where both Mathieson, a Sonoma County resident, and his suspected killer, Thomas Edward Halloran of Novato, were shot and killed.

He said only that Halloran was shot in the head by the brother of Halloran's former girlfriend as Halloran was trying to take the brother's and ex-girlfriend's mother hostage.

The ex-girlfriend, who also was not identified, fled to a neighbor's  after Halloran allegedly shot Mathiesen twice in the torso. She  was not present while the hostage-taking unfolded.

Duenas said Sonoma and Marin county detectives are investigating whether Halloran, who spent eight months in prison, may have formed gang ties while incarcerated. For that reason, they did not want to release the names of the ex-girlfriend or her family.

Duenas said Halloran, who has a past conviction for making felony terrorist threats, had two prior restraining orders on him -- one from an ex-wife and the other from another ex-girlfriend.

The current ex-girlfriend, who had ended the relationship nine days ago, did not have a restraining order on Halloran because, "she didn't think he knew where she lived," Duenas said.

The woman and Halloran had dated about two or three months, after meeting in March of this year, Duenas said.

Mathiesen went to the Petaluma home to help counsel the ex-girlfriend, a family friend, after Halloran had texted her a death threat. Duenas said Mathiesen was off-duty and unarmed.

Mathiesen is survived by a wife and two grown sons, Duenas said.