Expert: St. George teen's smoking backpack would not have exploded

It was the first day of a preliminary hearing to determine if there is enough evidence to advance the case against a southern Utah teenager accused of fashioning a makeshift explosive device and attempting to detonate it at Pine View High School in March.

A judge did not issue a ruling Friday following the expert testimony. If the case proceeds to a trial, prosecutors have said they intend to ask that the 16-year-old Pine View High School student face the charges as an adult.

The boy is charged in 5th District Juvenile Court with attempted murder and using a weapon of mass destruction, first-degree felonies. KSL has chosen not to identify the teen at this time.

School surveillance footage shows the teen depositing one of two backpacks near a vending machine at lunchtime on March 5 before opening it, lighting a fuse and walking away, court documents state. Students alerted teachers and a school resource officer after they saw smoke and a strong odor coming from the backpack for up to a minute, according to the charges.

Michael Truebenbach, a bomb expert with the FBI, testified Friday that materials in the backpack constituted an improvised incendiary device that could have started a large fire. But it wouldn't have exploded because sufficient pressure would not have built up to create such a reaction, he said.

"It would create a large thermal event, a large burning area," Truebenbach said.

Components of the device included a metal can, three plastic bottles with gasoline, metal balls, a smokeless powder and a time fuse with tape that was burned and charred, Truebenbach said. Despite the blackened tape, the fuse didn't function and the powdered fuel inside didn't combust, he said.

"It did not perform as a functional time fuse," Truebenbach said.

In an interview with police, the teen said "I would have been fine with it," if some of his classmates had been killed, according to the charges.

The student added that if he had been successful, he would have "laid low" for a while to gauge people's reaction and then tried to hang an ISIS flag at a school or on the freeway to make it look like ISIS had a presence there, charges state. He said he might try to contact the group after that but wasn't sure how.

The teen is also charged with graffiti and abuse of a flag, both misdemeanors, after police said he cut up an American flag at Hurricane High School and replaced it on a flag pole with a homemade ISIS flag. Additionally, he is accused of spray painting "ISIS is comi--" on a school wall.

Outside the courtroom Friday, Deputy Washington County Attorney Angela Adams said she is seeking for the boy to be tried as an adult, "mostly because of the risk to the community."

The teen is due back in court on Wednesday for a routine weekly hearing. Further dates for the preliminary hearing have not yet been scheduled.