Hosam Smadi parked a sport-utility vehicle in the garage beneath a Dallas skyscraper, activated a timer connected to what he thought was a bomb and used a cell phone to try remotely detonating the explosive he had spent months working to obtain.
Smadi, 19, who pleaded guilty Wednesday to attempted use of a weapon of mass destruction, had hoped the bomb would bring down the 60-story building, kill thousands of office workers and create financial havoc.
Instead, he was arrested, having been supplied with a fake truck bomb by undercover FBI agents posing as al-Qaida operatives.
U.S. District Judge Barbara Lynn deferred a decision on whether to accept the Jordanian teenager's plea Wednesday, saying she preferred to hear more evidence and wait until sentencing. She did not immediately schedule a sentencing hearing. His trial had been set for next month.
The charge is punishable by life in prison, but if Lynn accepts the plea agreement, Smadi would serve no more than 30 years and then be deported. Prosecutors have agreed to drop a charge accusing him of bombing a public place.
"Today's guilty plea underscores the continuing threat we face from lone actors who, although not members of any international terrorist organization, are willing to carry out acts of violence in this country to further the terrorist cause," said David Kris, the assistant attorney general for national security.
Peter Fleury, Smadi's public defender, told the judge that a prison doctor and a physician working for the defense have diagnosed his client with schizophrenia. Smadi is taking anti-psychotic and antidepressant medications.
"I feel differently when I take them," Smadi told the judge.
Fleury has argued in earlier court filings that Smadi exhibited signs of depression and mental illness when his parents separated and that he "completely fell apart" when his mother died of brain cancer.
After the hearing, Fleury said his client is neither political nor religious.
"This case has been a complete mystery," Fleury said. "Everybody who has met Hosam Smadi thinks he is a nice, kind, generous man. And yet he did this terrible thing."
Throughout the rearraignment hearing, Lynn took pains to ensure Smadi understood the ramifications of his plea. An interpreter translated her questions into Smadi's native Arabic. Smadi, wearing an orange prison jumpsuit and leg shackles, said he understood her and frequently responded directly to Lynn in accented English, politely addressing her as "Judge" and "Your Honor."
Smadi said he came to the United States when he was 16 and was educated here through the 11th grade.
When questioned by the judge, Smadi acknowledged leaving what he thought was a truck bomb in a garage beneath the 60-story Fountain Place building in September.
In his signed statement, Smadi said he parked the truck, activated a timer connected to the decoy, then rode away with an undercover agent and waited to watch the explosion.
The FBI said it had been monitoring Smadi after discovering him on an extremist website last year. Investigators said he acted alone and wasn't affiliated with any terrorist organizations.
Immigration and Customs Enforcement officials have said Smadi came to the U.S. on a tourist visa in 2007, but overstayed the time he was allowed to be in the country.
Associated Press writer Terry Wallace contributed to this report.
© Copyright 2016 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.