A spokesman for the U.S. Forest Service in California fatally shot his wife, himself and their two dogs after calling police and saying his wife was sick and no longer wanted to live, authorities said.

Matt Mathes, 54, and Karen Pang Mathes, 52, were found dead Saturday in their northern California home from gunshot wounds in what police described as a "homicide-suicide."

A man identifying himself as Matt Mathes called police Saturday morning and said in a "matter of fact" tone that he intended to kill himself, his wife and their dogs, said police Sgt. Craig Nickles in the city of American Canyon.

"They lived alone, they had no close relatives, and they probably wanted to make sure someone knew about the situation," Nickles said Tuesday.

Nickles did not know the nature of Karen Mathes' illness. An autopsy was performed, but its findings will not be available for some time, Nickles said.

Colleagues recalled Mathes as a principled and hardworking spokesman for the Forest Service, one with an encyclopedic knowledge of its history in the region. They knew of no serious personal problems, they said.

Mathes had served for 29 years with the Forest Service, 17 of them in the agency's San Francisco-area offices, said Jason Kirchner, another spokesman who shared an office with Mathes.

Mathes had been an enthusiastic and knowledgeable source for reporters throughout the region, most recently on the Southern California fires last month and the Lake Tahoe wildfires last summer that destroyed some 3,100 acres.

"He was very passionate about the Forest Service as an agency," Kirchner said Tuesday. "He was one of those people who seemed to truly believe in our mission — caring for the land and serving the people."

Mathes was eligible to retire when he reached 55 and had 30 years in at the Forest Service — milestones that were just months away, Kirchner said. Although he occasionally talked about retirement, "he never seemed ecstatic about leaving," Kirchner said.

"He seemed to love working here every day. He was always at his best when we were in a crisis mode or there was some emerging issue," Kirchner said.

Last weekend Mathes was midway through a two-week vacation, Kirchner said. He had told Kirchner he planned to spend the break with his wife, whom he sometimes referred to as "Precious," Kirchner said.