John Carr, spokesperson for California's Department of Alcoholic Beverage Control, tells TMZ that his agency wants to review witness reports and other evidence to determine if a formal investigation is warranted. Carr says his agency also wants to know if Lohan or others may have been served after hours.

Lindsay Lohan was arrested and cited for DUI on Saturday morning after her Mercedes struck a curb on Sunset Blvd. Lohan was hospitalized for minor injuries – and police said they found a substance tentatively identified as "a usable amount" of cocaine in connection with the accident.

Lohan then headed out just one night later to a private bash in a poolside room at the Hollywood Roosevelt Hotel.

"The police intervening is a wake-up call," says one. "This could be the best thing for her. I think she'll have to do a real rehab this time, and not just a Hollywood rehab." Says another: "Everyone has tried to step in," says a good friend. "You can't make someone get help unless they want to."

"She cares about her craft and about her career," says a source. "She wants to be a Jodie Foster, so when she does things that are affecting her progress, that makes her upset."