Two co-defendants, one of them a Mesa man, pleaded guilty to reduced charges Tuesday in the O.J. Simpson armed-robbery case, agreeing to testify against Simpson and three others in the alleged theft of sports collectibles from two memorabilia dealers.

Behind the scenes, prosecutors prepared to file an amended criminal complaint increasing the number of charges in the case to 12, including a second felony charge of coercion against Simpson and two new coercion charges each against the three remaining co-defendants.

The new complaint also alleges Simpson and Charles "C.J." Stewart conspired to persuade others to tell authorities that no guns were used.

The revised document, obtained by the Associated Press, removes Walter Alexander of Mesa and Charles Cashmore from the case, while naming Thomas Riccio in the Sept. 13 meeting between Simpson and memorabilia dealers Bruce Fromong and Alfred Beardsley.

Riccio, who was given immunity from prosecution, is expected to join Cashmore and Alexander in testifying for the prosecution.

Alexander pleaded guilty to the felony of conspiracy to commit robbery.

The district attorney said he would seek a suspended sentence for Alexander, a golfing buddy of Simpson's. "I'm very much at peace at what I've done today and what I'm going to continue to do," Alexander said as he clutched a Bible outside court. "I'm not here to try to hurt or help O.J. Simpson. I'm only here to tell the truth."