Troubled celebrity Lindsay Lohan is under investigation for alleged battery of a worker at a live-in drug and alcohol rehab clinic, police say.
Police said they were called to the Betty Ford Center in California on 12 December after a report of an assault.
US media reported the incident occurred when staff confronted Ms Lohan after she returned late to the clinic.
The Mean Girls star was ordered to the rehab programme in October after failing a court-ordered drug test.
"The victim desires prosecution," Riverside County Deputy Sheriff Herlinda Valenzuela said, according to the Associated Press news agency.
The case is still under investigation and further details were unavailable.
However, Betty Ford spokesman Russ Patrick said the staff member who had made the complaint had now been sacked for breaking patient confidentiality.
The employee conducted an interview with celebrity website TMZ on Tuesday.
Ms Lohan is due to be released from the clinic next month.
Ms Lohan was convicted of drink-driving in 2007 and failed a random drug test this year, causing a judge to commit her to the rehab centre.