A man was arrested after impersonating a cop while robbing another man at San Francisco's Parkmerced apartment complex early this morning, police said.
The robbery was reported at 3:06 a.m. in the 300 block of Font Boulevard.
The 19-year-old victim was chased by a suspect who claimed to be a police officer. The suspect caught up to him, beat him, and demanded money, then snatched a necklace from him and fled, according to police.
The suspect, a 21-year-old man, was subsequently arrested, police said.
The victim suffered an abrasion to his elbow and complained of pain in his mouth, but did not require hospitalization.