RICHMOND, Va. -- After a weeklong trial and nearly four days of deliberations, a federal jury convicted only one of four Outlaws motorcycle gang members on trial for racketeering and failed to reach a verdict on the organization's president.

Two members were acquitted Wednesday after a more than two-year undercover operation that resulted in charges against 27 members of the biker gang.

The jury was unable to reach a unanimous verdict on Outlaws national president Jack Rosga of Milwaukee, who was charged with conspiracy to commit racketeering and conspiracy to commit violence in the aid of racketeering. Rosga showed no emotion as the deadlock was announced.

Peter Duffey, the lead federal prosecutor in the case, said Rosga will be retried. U.S. District Judge Henry E. Hudson said a trial date will be set next week.

Leslie Werth, a leader in the Outlaws' Rock Hill, S.C., chapter was convicted on the same charges facing Rosga. He was acquitted of using violence in the aid of racketeering and a firearms charge.

William Davey of Asheville, N.C., was acquitted on four charges and Mark Spradling of Hickory, N.C., was found not guilty of two charges.

Davey's attorney, Horace F. Hunter, said his client was thrilled to be exonerated and going home, and that Rosga also should be pleased that the jury couldn't reach a decision on his case.

"To not get a verdict on Jack Rosga is certainly a victory for him and a defeat for the government," Hunter said.

The U.S. attorney's office did not immediately respond to a request for comment.

The government claimed that Rosga led a criminal enterprise responsible for an array of violent crimes, most of them aimed at gaining an advantage over the rival Hell's Angels motorcycle gang and its allies.

"There are always going to be a few bad apples," Hunter said. "This is an organization of over 600 people."

The government's star witness was an undercover agent who infiltrated the Outlaws for more than two years and established a chapter in Petersburg, Va. He testified about a number of violent or tension-filled conflicts between the Outlaws and their rivals.

Fifteen of the biker gang members who were indicted in June have pleaded guilty. One was killed by federal agents as they tried to arrest him in Maine, and charges were dropped against one. Six others have yet to be tried.