A capital murder charge was filed Thursday against a West Valley man accused of detonating a bomb last week and killing an 11-year-old boy.

Salt Lake County Attorney David Yocom filed the aggravated-murder charge against Steven Douglas Thurman, 32, just hours after Adam Cook died at University Hospital. The young bombing victim died at 12:12 a.m. Thursday without ever gaining consciousness, said hospital spokesman John Dwan.If convicted, Thurman, 3843 W. Rockwood Way, could receive the death penalty.

Prosecutors also charged Thurman with delivering an infernal machine, a second-degree felony, and construction of an infernal machine, a third-degree felony.

Adam Cook was injured May 15 when a nail-studded pipe bomb exploded as

he was sitting in a vehicle owned by his father, Howard Cook.

Police arrested Thurman Friday, and he was charged with one count of possessing an unregistered explosive. That federal charge, however, was dismissed Thursday after the murder charge was filed. Thurman remains held without bail in the Salt Lake County Jail. His arraignment is scheduled Friday in 3rd Circuit Court.

At this point, the state intends to push for the death penalty, Yocom said. "The state statute provides that when a device of this type is used, it is a capital offense."

Police arrested Thurman after searching his apartment, where they found wire connectors, duct tape, black powder and wiring.

According to a complaint filed in federal court, the force of the blast lodged an AA-size battery in the boy's brain.Officials have said they believe the bomb was intended for the boy's father. The complaint filed against Thurman says Cook had been involved in a relationship with Thurman's ex-wife.

Wendy Thurman and Howard Cook both worked at Metz Baking Co., where there was a bomb threat the day before the boy was injured. Police searched the company and its vehicles without finding anything.

Howard Cook was waiting in a friend's house for his son to return from a Boy Scout meeting. The boy apparently returned to the vehicle and honked the horn just as the bomb exploded. Police believe the bomb was detonated by remote control.

According to court documents filed Thursday, Thurman admitted that he was thinking about making a bomb about one month ago, when he purchased a pipe. Based on a change in Utah law, the aggravated-murder charge replaces the old charge of first-degree murder.

After the blast, the boy was in the University Hosptial's neuro critical care unit with head and eye injuries.