He was arrested in Sacramento on domestic violence charges. Here's the bloody details:
Sacto 9-1-1: Ex-Kings player Matt Barnes arrested
Sacramento County Sheriff's spokesman Sgt. Tim Curran said deputies responded to an incomplete 911 call from the 8100 block of Sunset Avenue at about 4:15 p.m., where they encountered Barnes and a woman "who lived with him and with whom he had a dating relationship."
After speaking to Barnes and the woman, deputies determined that the two had been in a physical confrontation and Barnes had prevented the woman from talking to 911 operators. Curran said dispatchers heard the sound of a struggle in the background on the brief open line until it was disconnected.
Both parties had visible injuries but Barnes was determined to be the primary aggressor, Curran said.
There's a joke here about Barnes being on the same team now as Kobe Bryant and Ron Artest but for some reason it escapes me.