Three people have been arrested in the killing of a California yoga teacher who was shot on a trail in what appeared to be a random crime while walking his dog, authorities said Wednesday.

Marin County sheriff's Capt. Dave Augustus described the three people taken into custody in Portland, Oregon, as drifters and said a motive was unknown.

The body of Steve Carter, 67, was found Monday in Marin County, where he was living and caring for his cancer-stricken wife Lokita Carter.

Authorities previously said they were seeking three people whose images were captured on a nearby surveillance camera at a nearby convenience store.

Authorities believe Carter drove to the trail near Fairfax in his 2003 Volkswagen that was missing after the attack.

Followers credited Carter with improving their romantic relationships by teaching tantra, a philosophy of meditation, yoga and sexuality famously embraced by the rock star Sting.

Stunned students and supporters mourned their beloved teacher who was still holding the leash of his wounded Doberman pinscher when he was found. The dog is expected to recover.

The Carters launched the Ecstatic Living Institute in rural Middletown, California, about 16 years ago to teach tantra to couples around the world. They held workshops nearby at the clothing-optional Harbin Hot Springs, which was destroyed last month in a wildfire.

"He was my mentor," said Greg Whitmore, 37, a firefighter who attended several weeklong retreats led by the Carters. "It was intoxicating. People wanted to be around him."

Last year, the couple turned the institute over to a former student, Logan Rose, and moved to Costa Rica in semi-retirement, teaching an occasional class. But soon after moving, Lokita was diagnosed with breast cancer.

"It has been a very traumatic season for us with Lokita's cancer, then the Valley Fire that destroyed our beloved Harbin Hot Springs," Rose said.

"This is the most devastating blow," Rose said of the homicide. "We are heartbroken."

Lokita Carter didn't respond to requests for comment.

Followers, students and friends have been pledging money and offering sympathy,

Joya Petra Gallasch said in an interview that Carter was responsible for adding her new first name during a training session at Harbin Hot Springs. Gallasch said she was depressed at the time and Carter led her to adopt the new first name of Joya.

"I've always been a super joyous person," Gallasch said. "He knew intuitively that it was time to get a new name. He exuded a form of brilliance."

A hiker found Carter's body. Sheriff's deputies responding to a report of shots fired 45 minutes earlier in the area didn't see anything suspicious.

Carter's brother, Michael Carter, said he knew of no one who disliked his brother.

"I can't imagine that it's anything other than a random thing," he told the San Francisco Chronicle. "All of it seems very random and unbelievable. Nothing makes any sense."