Updated

DALLAS -- A 20-year-old Jordanian man caught in an FBI sting trying to blow up a Dallas skyscraper was depressed and slept by his mother's grave after her death from cancer, his father testified Monday during a sentencing hearing.

Hosam Smadi faces up to life in prison after pleading guilty in May to attempted use of a weapon of mass destruction. Under his plea agreement, however, it is likely he will receive a 30-year sentence and then face deportation.

Smadi's father said his son also stopped eating after his mother died of brain cancer about five years ago.

According to the pleading documents, Smadi acknowledged leaving what he thought was a truck bomb in a garage beneath the 60-story Fountain Place building in September 2009. Smadi said he parked the truck, started a timer connected to the decoy provided by undercover FBI agents, then rode away to watch the explosion.

Smadi dialed a cell phone number from the roof of a nearby parking garage, where he had planned to watch the explosion. The number was supposed to set off his truck bomb. It instead alerted tactical agents hiding in a stairwell, who swarmed the rooftop and arrested the teenager.

Posing as members of an Al Qaeda sleeper cell, three undercover FBI employees had monitored Smadi since January 2009. After he shared his plans to blow up the office tower, they helped him secure a truck and fake bomb used to carry out the mission, according to court documents.

Since the arrest, Smadi's public defenders have portrayed their client as a troubled and depressed young man, who exhibited signs of depression and mental illness when his parents separated. At the plea hearing in May, attorney Peter Fleury said Smadi had been diagnosed with schizophrenia by a prison doctor and a physician working for the defense.

FBI officials, however, tell a different story. After monitoring Smadi for nine months, they say the defendant was a committed would-be terrorist determined to connect with Al Qaeda or Hamas. It was fortunate, they say, that they found him first, spewing hatred for America on an extremist website.

"Smadi was asked what he would do if he had never met the Al Qaeda `sleeper' cell," said Tom Petrowski, a supervisory special agent with the FBI in Dallas, in an affidavit. "Smadi replied that he would keep looking for such an entity to be a part of, even if it meant him having to leave the United States and go to Palestine and join Hamas or go back to Pakistan and join the Taliban."