Lindsay Lohan was arrested on suspicion of driving under the influence early Saturday morning after her Mercedes convertible struck a curb on Sunset Boulevard in Los Angeles. Police reported that they also found a substance they believe to be cocaine at the scene, according to an Associated Press report.

Lohan, 20, and two other unidentified people were in the actresses' 2005 Mercedes SL-65 when it crashed at around 5:30 a.m. on Saturday. It appeared she had been speeding and when police responded to a 911 call about the accident, the AP reported that officers found a "usable amount" of a drug they tentatively identified at the scene as cocaine. They would not say where the drug was found other than to confirm that Lohan was not carrying it.

Lohan — who spent time in a rehabilitation facility earlier this year and has said in interviews that she's been attending Alcoholics Anonymous meetings for more than a year — was driven from the scene in a different car to the hospital to be treated for minor injuries; the other two people were not hurt.

Lohan was arrested at the hospital for investigation of misdemeanor driving under the influence of alcohol or drugs, then released when she was admitted for treatment. Police declined to tell the AP what her blood-alcohol level was, but said the case would be presented to the district attorney's office, where she could face additional charges, some of them felonies. Her tentative arraignment date is August 24.

Saturday's incident was the third car wreck in the past two and a half years for the troubled actress. In October 2005, she and a passenger sustained minor injuries when her convertible hit a van in Hollywood in an incident in which police cited the other driver (see "Lindsay Lohan Taken To Hospital After Car Accident"). Just months before that, Lohan struck a minivan carrying a paparazzo, when she made a U-turn to try and avoid the photographer, who was arrested for investigation of assault with a deadly weapon, but not charged.

At press time, Lohan's publicist had not responded to requests for comment.