OGDEN -- Detonation of a bomb at a Roy High School assembly was planned for early February, Roy Police Chief Greg Whinham said Friday.
That is evident in the loose details investigators have uncovered so far, Whinham said. More will be revealed once the suspects' computers are searched, he said, hopefully within weeks, not months.
Planning by the two teens arrested Wednesday began in October, he said. The "front end" and the "escape end" were more developed, the chief said, but the mechanism, the actual bomb, hadn't yet been decided on.
"There never really was one plan," Whinham said. "There were a couple plans."
He noted co-defendant Joshua Kyler Hoggan, 16, was on the audio-visual crew that sets up lighting, sound and video at Roy High assemblies, but Whinham declined to give further details.
Prosecutors filed a first-degree felony charge of possession of a weapon of mass destruction Friday morning against Dallin Todd Morgan, 18, for his part in the conspiracy. He is scheduled to be arraigned on the charge Wednesday in 2nd District Court.
He was released from jail on $10,000 bail shortly after his arrest on suspicion of possession of explosives Wednesday before a formal charge was filed.
Officials said he was expected to be rebooked Friday on the mass destruction charge with its higher bail of $20,000.
Hoggan remains in custody in juvenile detention. A judge ruled against his release during a detention hearing in juvenile court Friday morning, where Whinham said he understood Hoggan was charged with the same offense.
Juvenile court proceedings are confidential, and officials there declined to comment.
State courts spokeswoman Nancy Volmer said she couldn't confirm the charges against Hoggan.
The plans for the attack included stealing a plane from Ogden-Hinckley Airport to make their getaway, according to charging documents.
"We ain't gonna crash it, we're just gonna kill and fly our way to a country that won't send us back to the US," Hoggan is quoted as texting a friend.
The recipient on Wednesday alerted school authorities, who then called police.
Hoggan noted in another text that Morgan "wants revenge on the world too ... We both want to, and we have a plan to get away with it too."
Hoggan's apparent reference to a motive for killing his fellow students was "Life ... plus a huge ass backstory that make me hate people."
"Another reason is I just don't care. I'm pretty much a lying cheating manipulator with everyone except seven people. Everyone else is just a piece."
The two female recipients of Hoggan's texting reported the lengthy messages to school officials, who contacted police.
Bomb-sniffing dogs and a bomb squad searched the school for 2 1/2 hours Wednesday but found no evidence of explosives.
The charge of possession of a weapon of mass destruction includes the wording conspiracy, attempting to possess or soliciting as violations of the statute.
Normally the names of juvenile suspects under the age of 18 are not made public, but Whinham said releasing Hoggan's was "for investigatory purposes."
"We've got a timeline going back at least to October," he said, "so a lot of people could have had contact with them.
"They could have heard either one of them say something, or purchase something, do something, that didn't mean anything at the time, but means something now."
Morgan and Hoggan have been banned from all Weber School District campuses, said district spokesman Nate Taggart.
"It's a no-trespass order, which is given to the individual," he said, although one hasn't been handed to Hoggan, because he is being held in the Weber Valley Detention Center in Roy.
"It's certainly expected that anybody at any of our schools that saw either of them would report it," Taggart said. "This is the process that takes place with any of our suspended students."
Whinham said his department has been inundated with not just local media, but national as well, including "Good Morning America" and CNN.