Two teenage siblings arrested in the gunshot slaying of a Spokane man remain jailed on $1 million bond after appearing in court Monday.

Breeanna C. Sims, 19, and Justice E. Sims, 18, faces charges of first-degree murder, second-degree arson, first-degree kidnapping and first-degree rendering criminal assistance for the death of 22-year-old Nicholas J. Thoreson, who was found shot to death April 13 in the burning trunk of his 1987 Ford Thunderbird at Forker and Bigelow Gulch roads.

Taylor J. Wolf, 20, who was arrested 22 hours after Thoreson's body was found, is jailed on a second-degree murder charge but expected to soon face the same charges as the Sims, authorities say.

Breeanna Sims was arrested Friday afgter they followed her to Forker and Bigelow Gluch, where she was looking for evidence. A sheriff's dog led detectives to a .38 caliber pistol and a sawed-off 12 gauge shotgun. The pistol is believed to have been used to kill Thoreson.

Justice Sims was arrested after leaving his apartment in north Spokane, where detectives had set up surveillance. He flashed a hand sign at supporters before being led out of District Court after his first appearance Monday.

No motive for the slaying has been released. Wolf has ties to the Hells Angels motorcycle gang and worked briefly at Fessco Fleet & Marine with the gang's enforcer, Ricky Jenks, who is jailed on federal guns charges. Investigators haven't said if Thoreson's murder is related to the Hells Angels.

Affidavits detailing the case remain sealed, though Spokane County sheriff's Sgt. Dave Reagan said there are no other suspects. A status conference for the case is set for April 21.

Thoreson was the father of an 11-month-old baby. Friends say he knew Wolf through a job corps program.

Thoreson's mother, girlfriend and other friends attended Monday's hearing but declined comment.