This silver PT Cruiser with an Alberta rear licence plate was found in the parking garage of a Vancouver condominium in which Ryan Jenkins's half-sister Alena is a registered owner. (CBC)

Investigators believe the mystery woman who drove accused murderer Ryan Jenkins to a Hope, B.C., motel days before he hanged himself was his half-sister, a police source has told CBC News.

Jenkins, a Calgary businessman who was competing in a reality TV show in California, was found hanged in his room at the Thunderbird Motel on Sunday. He had been charged in the death of his wife, model Jasmine Fiore, and was the focus of an international manhunt.

Initially, there was speculation that the woman who arrived at the motel driving a silver PT Cruiser with Alberta licence plates was Jenkins's ex-fiancée, Paulina Chmielecka, after motel staff identified her from photographs.

But on Tuesday, a police source said police believe the mystery woman who checked Jenkins in to the motel was his younger half-sister, Alena Jenkins, 19. The source said police have spoken to the woman, but have not laid any charges.

The source also said the woman was familiar with Point Roberts, Wash., a small peninsula just south of Vancouver where the Jenkins family has a large cottage. That's also where Jenkins is believed to have crossed the border into Canada after fleeing nearby Blaine in a boat.

Car possibly located

A silver PT Cruiser car with Alberta plates was found Wednesday by CBC News in the parking garage beneath a luxury highrise in the Coal Harbour neighbourhood of Vancouver. Alena Jenkins is the registered owner of a condominium in the building.

The RCMP have refused to officially release any specific information about the woman who checked Jenkins in to the motel, including her identity, whereabouts or whether she was in police custody. But they did say Monday they have identified her and she is not considered a risk to public safety.

After Ryan Jenkins' body was found Aug. 23 hanging from a coat rack at the Thunderbird motel, the assistant manager was clear about how Jenkins got there on the prior Thursday.

"It was a lady in a PT Cruiser, a silver one," Adam Burt Told CBC News. "And Alberta plates, we noticed that, too."

Staff of the Thunderbird Motel in Hope, B.C. said a woman in a silver PT Cruiser with Alberta licence plates checked Jenkins into the hotel on Thursday. (CBC)

RCMP also said the woman could be charged by Canadian authorities for helping Jenkins illegally enter Canada, and could also be charged by U.S. authorities with being an accessory after the fact for the murder of Fiore.

Guests at the motel told reporters on Monday that the woman left almost immediately after checking in, and it appeared Jenkins was alone when he hanged himself on Sunday. His body was discovered later that day by motel staff after he failed to check out.

Jenkins, a 32-year-old real estate developer and investor from Calgary, was charged with first-degree murder in California last Thursday after Fiore's dismembered body was found in a suitcase in a dumpster in Buena Park, about 32 kilometres southeast of Los Angeles, on Aug. 15.

In another development Wednesday, officials report that a Mercedes-Benz believed to be Fiore's was found in the parking lot of a West Hollywood, Calif., grocery store just before 1 p.m. PT.

The car was dusty, dirty and had no licence plates, but does match the description of the one missing, according to a spokesperson for the Los Angeles County sheriff's office.

While Ryan Jenkins's immediate family has remained silent, another close relative issued a statement.

"The events of the past week have been a surreal experience for my entire family. None of what has happened fits with the Ryan we all knew and loved so dearly. I only hope with diligent investigative work the real truths will emerge," the statement said.