CSI Star Arrested For Allegedly Breaking Girlfriend's Nose

We're told a former girlfriend went to Dourdan's home in Venice, CA Sunday night. Cops received a disturbance call at around 9 PM, arrived at the house but the woman had already left. While the cops were there, someone called LAPD and said an injured woman was in a nearby alley -- it was Dourdan's ex. Cop looked her over and it appeared she had a broken nose and she said Dourdan was the culprit.