A teenage girl and her younger brother remain in custody while police try determine what drove them to allegedly kill a relative who was found dead in a scorched car in Juab County Wednesday.

Provo Police Capt. Keith Teuscher said detectives want to determine why there was "so much anger" toward 30-year-old Samuela Pulupaki Loseli, who is related to the teenagers by marriage."Something set it off, no doubt," he said.

Police continue to provide few details about the killing. Teuscher said detectives are having difficulty sorting out conflicting stories.

Latina Lolohae, 17, Orem, and her 15-year-old brother appeared at a detention hearing Friday in 4th District Juvenile Court. The judge determined authorities have cause to keep the pair at the Slate Canyon Youth Center, a detention facility in Provo. No charges have been filed.

Utah County Attorney Kay Bryson said prosecutors told the judge they would have an idea by Tuesday where they are headed with the case. Teuscher said detectives want to finish their investigation Monday or Tuesday. Police interviewed members of both families, including Loseli's wife, Friday. Detectives also dusted the Loseli's Provo apartment for fingerprints.

Loseli was watching television in the living room of his apartment, 615 N. 600 West, late Tuesday just before he was struck in the head, Teuscher said. Loseli's wife was asleep in the bedroom and apparently didn't hear anything, he said. Detectives said there was no sign of a struggle inside the apartment. Investigators, he said, don't know whether Loseli died before he was driven to Juab County.

A cattle rancher came across Loseli's Ford Taurus Wednesday morning just off a dirt road five miles west of I-15 near Mills. Juab County sheriff's deputies discovered Loseli dead in the back seat. A small gasoline-fueled fire charred a piece of the interior.

Teuscher said Loseli's assailants left Juab County in another vehicle.

Latina Loseli turned herself in to Orem Police Wednesday night. Orem Police Lt. Karl Hirst said she wanted to tell officers about a homicide in Provo. Provo police later interviewed her brother before taking both teens to the youth detention center. Teuscher said police have been unable to question the teenagers a second time, which has made it difficult for police to offer a motive for the slaying.

Teuscher said detectives are exploring the possibility that the killing of Loseli was retaliatory.

Members of the Lolohae family declined to comment when approached at their Orem home Friday afternoon. They said they were in the middle of a family council and didn't want to answer any questions.

Loseli's neighbor and a co-worker said Loseli was not a violent person. They said they knew him to be quiet and passive.