SANTA ANA, Calif.—Prosecutors on Friday argued that a former FBI agent armed himself with a machine gun, assault rifle and more than 600 rounds of ammunition to rob a drug stash house in Southern California.

But attorneys for Vo Duong Tran, 44, of New Orleans, said he was just playing along in an attempt to collect evidence on a man he thought was a criminal but turned out to be an FBI informant.

After more than three weeks of testimony, attorneys wrapped up closing arguments Friday in the trial of Tran and Yu Sung Park, who face federal charges of conspiracy to obstruct commerce by robbery, interstate travel to commit a crime with a firearm, possession of a firearm in furtherance of a violent crime and possession of a machine gun.

Tran and Park were arrested in July and accused of planning to rob what they believed was a Mexican drug courier's stash house in suburban Fountain Valley. But the house was actually part of an FBI sting and the man who had pitched the robbery scheme was an agency informant.

Assistant U.S. Attorney Ivy Wang showed the jury a machine gun, a rifle equipped with a silencer, handguns, bulletproof vests, fatigues, zip ties, a black ski mask and more than 600 rounds of ammunition retrieved from a rental car and motel room used by the two men the day before the robbery was allegedly going to happen.

"They had these tools because they were ready to commit a home invasion robbery," Wang said. "They're not amateurs.


They are knowledgeable and they are prepared."

Authorities said the arrests followed a federal probe in which conversations were secretly taped for nearly six months. They said Tran flew from New Orleans to raid the home, where the informant had told him there was $300,000.

Tran was an FBI agent in Chicago for more than a decade before being fired in 2003.

Defense attorneys said Tran was passionate about his law enforcement career and was simply playing along with the robbery scheme to gather evidence on informant Alex Dao so he could turn him over to authorities.

"Mr. Tran was trying to gather information on somebody he believes is a criminal and should be turned over," Brian Steel, one of Tran's defense attorneys, told jurors. "He enjoyed law enforcement, he is still wrapped in it."

Park, 36, of Metairie, La., used to work at a cell phone store owned by Tran. He had come to Southern California to meet his former employer and played along when asked, said Yolanda Barrera, his defense attorney.

"Look at the language he's using," Barrera said of recordings where Park explained how to clear a house before a robbery. "That's straight from television. That's straight from video games."

If convicted, both men could face maximum sentences of up to life in prison, defense attorneys said.

Alex Kessel, one of Tran's attorneys, said his client was terminated from the FBI for identifying himself as an agent while he was on suspension—a charge for which later he wasn't convicted.

Kessel said the only reason an experienced former agent would carry these weapons, some which were registered to Tran, is because he didn't plan to commit a crime.

But prosecutors scoffed at that argument and replayed recorded conversations where the men discussed whether to handcuff residents during the robbery or shoot them. They also pointed out Tran never told police about his probe of Dao.

"The argument there's so many guns that it proves innocence is kind of an odd proposition," said Robert Keenan, an assistant U.S. attorney.