The deal with Keller suggests prosecutors might try to use him as a star witness at upcoming trials, banking on his notoriety as a decorated athlete who won gold medals in swimming at the 2008 Beijing Olympics and the 2004 Athens Olympics.
Keller was arrested in January and charged with seven crimes. The other charges will be dropped as part of the plea deal. He pleaded guilty to a felony charge that could potentially lead to prison, though he could reduce his sentence by helping prosecutors.
Until now, the only rioters who have struck cooperation deals were members of extremist groups who could testify against their fellow members.
This story is breaking and will be updated.
