A prosecutor told jurors Monday they will learn "the true face" of O.J. Simpson during the former football star's trial on charges of robbing sports memorabilia dealers in a Las Vegas hotel room.

Prosecutor Chris Owens began his opening statement by playing an audio recording of the confrontation and pointed out one voice barking commands: "Don't let nobody outta here ... stand the [expletive] up before it gets ugly in here."

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Simpson, who flashed a thumbs-up sign when he arrived at court, sat impassively while Owens described the rest of the recording.

"The audio will show threats, it will show force, it will show demands and it will show the taking of property from the victims in this case," Owens said.

"In our presentation of the evidence we are going to spend the next few days finding which may be the true face of ... Simpson, not necessarily the one he tries to put out to the world," Owens said.

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In his opening statement, defense attorney Yale Galanter asserted that the evidence will not show that Simpson intended to commit a crime, but rather that he simply wanted to recover stolen personal effects, including pictures of his deceased parents, and not sports memorabilia.

"You can think what you want about his past, and you all as jurors have agreed to ignore that ... what you're going to hear in this courtroom is not a case about hiding anything from anybody. It's a case about recovering personal items," Galanter said.

Simpson, 61, and co-defendant Clarence "C.J." Stewart, 54, a former golfing buddy from North Las Vegas, have pleaded not guilty to 12 charges including kidnapping, armed robbery and conspiracy. Each could face life in prison with the possibility of parole if convicted of kidnapping, and mandatory prison time if convicted of armed robbery.

Clark County District Attorney David Roger has said the case against the two men will rely on testimony from some 25 witnesses, including four former co-defendants who have taken plea deals and agreed to testify for the prosecution.

Stewart's attorney, Robert Lucherini, characterized his client as a successful mortgage broker who used his relationship with Simpson for networking, and on the day of the incident had simply been asked by Simpson for help in picking up his property.

Lucherini told the jury that unlike former co-defendants in the case, Stewart was on trial because he was of no use to the prosecution.

"These witnesses have been offered plea agreements, bargains, given immunity, in order for the state to help prosecute and convict O.J. Simpson," Lucherini said. "That's something that Mr. Stewart couldn't help them with because, one — and his story has never changed — he didn't know the property was stolen, and two, he didn't know there were guns going to be used in that room.

After opening statements, the prosecution is expected to call Bruce Fromong, a 54-year-old sports collectibles dealer from North Las Vegas to the stand, according to a witness list that Galanter said prosecutors shared with the defense.

Fromong testified at a hearing in November that he expected to meet with an anonymous buyer when Simpson arrived with others "in a military invasion fashion."

Fromong said one man wielded a gun while Simpson shouted that items in the room belonged to him and instructed the men with him to gather them up.

Simpson denies that guns were taken to the hotel room.

The prosecution audio recordings were surreptitiously made by Thomas Riccio, a Los Angeles collectibles trader who arranged the Sept. 13, 2007, meeting between Simpson, Fromong and sports memorabilia dealer Alfred Beardsley.

Galanter said the recordings could also help the defense, asserting that at one point, Simpson says nothing should be taken that isn't his.

"It'll be clear from the tapes when O.J. says 'Don't take any things that aren't mine,"' Galanter said.