Robert Dewey Hoskins, 54, allegedly walked out of the Metropolitan State Hospital Feb. 3 in Norwalk, CNN reported Friday.
He had previously served a 10-year prison sentence for stalking and threatening to kill Madonna -- he is required to spend time in the mental health facility until the end of August 2012, police said.
"At this point they are returning him to the facility, and I believe [the possibility of new charges] will be determined by the detectives who will investigate -- No. 1, his ability to walk away from the facility and, No. 2, if he violated anything from that point on," Los Angeles Police Sgt. Mitzi Fierro said.
After Hoskins escape, police issued a warning to the public, saying he "is highly psychotic when not taking his medication and has very violent tendencies."
Madonna testified he repeatedly scaled the fence at her California home and gave her nightmares, KCAL-TV, Los Angeles, reported. At one point he threatened to cut her from ear to ear if she did not marry him.