An FBI bomb technician testified Wednesday about his mood after the Nov. 26, 2010, arrest of Portland

.

"There was a sense of relief," John Hallock told the jury hearing the case against Mohamud in U.S. District Court. "A sense of shock and relief."

Hallock had created the fake fertilizer bomb that undercover FBI agents, posing as terrorists, had presented to Mohamud. The 1,800-pound device, loaded into a van and constructed of six 55-gallon barrels linked by detonation cord, had a blasting cap and a cell-phone detonation system with a toggle switch that looked authentic.

The bomb tech testified that he had designed the phony explosive so it was big enough -- were it real -- to destroy Pioneer Courthouse Square. The device was in fact filled with grass seed and other inert materials that -- along with diesel fuel -- were harmless.

»

Your guide to the story

»

»

»

»

"I built the device for maximum effect," Hallock said.

Jurors got to see the fake explosive in the basement of the federal courthouse on Friday, the end of the first week of testimony in Mohamud's terrorism trial. He is accused of attempting to detonate a weapon of mass destruction at Portland's holiday tree lighting ceremony.

Under cross examination by defense lawyer Lisa Hay, Hallock recounted some of the comments he and other agents made after Mohamud dialed the keypad of a cell phone to ignite what he thought was a real bomb and agents rushed in to arrest their suspect.

Hallock recalled that the FBI had already prepared a press release and that he made a bet with another agent about when TV news would broadcast the story. He also noted that he was surprised Mohamud hadn't caught on earlier to the sting operation that culminated in his arrest.

The bomb tech also recounted that he voiced his feeling about Mohamud after the teenager was in handcuffs: "He's done."

The trial continues before the jury at 1:30 p.m. with testimony from FBI Special Agent Elvis Chan, who took part in the undercover operation.