SAN FRANCISCO -- Three transients accused of using a stolen gun to rob and kill a Canadian backpacker and a yoga instructor two days apart were sent back Monday to Northern California from Oregon, where they were arrested.

Authorities say Sean Michael Angold, 24, Morrison Haze Lampley, 23, and Lila Scott Alligood, 18, killed backpacker Audrey Carey, 23, in San Francisco's Golden Gate Park on Oct. 3. They also are accused of gunning down tantra yoga teacher Steve Carter, 67, whose body was found Oct. 5 on a popular hiking trail in Marin County, 20 miles (32 kilometres) north of the city.

The three suspects were arrested last week at a soup kitchen in Portland, Oregon. They were travelling under guard from Portland and are expected to be booked in jail Monday, Marin County sheriff's Lt. Doug Pittman said.

They could make their first court appearance Tuesday, Pittman said. It's unclear if they have attorneys who could speak on their behalf.

California prosecutors must decide where Lampley, Angold and Alligood will stand trial first -- Marin County or San Francisco. Both county prosecutors said they expected to charge each of the three suspects with murder.

A San Francisco resident reported the theft of his handgun from his unlocked car parked in the Fisherman's Wharf neighbourhood on Oct. 1, police Lt. Toney Chaplin said. The stolen gun was found during the arrest of the three suspects, Chaplin said.

Detectives had tracked them to Portland through the navigation system of Carter's stolen car, investigators say.

Carter had driven to the hiking trail with his dog on the evening of Oct. 5. He lived nearby with friends while caring for his cancer-stricken wife. Carter was robbed, and his dog also was shot, investigators said.

The dog was turned over to an animal welfare group and is expected to survive.