The incident occurred on the third floor of University Park Apartments building 9 between 8 and 9 a.m.
Police said the suspect took the victim's wallet and several other documents before fleeing.
It remains unknown how the suspect entered the victim's apartment.
He was described as a black male, approximately 25 years old, 6 feet tall and weighing about 180 pounds with short black hair and dark-colored eyes. The suspect has a thin, athletic build with a scar on his chin.
He was last seen wearing a red Adidas hooded sweatshirt with white lettering and light-colored blue jeans.
The investigation is ongoing.
Police are looking into the possibility that the suspect may be connected to other recent attacks. His sketch is strikingly similar to one of the four suspects wanted for a series of incidents at the same apartment complex. In two of the three cases, the four suspects cornered women, making sexual comments and trying to grab them before they escaped.
Anyone with information regarding this incident or any similar incidents within the University Park Apartments was asked to contact Detective Sergeant Mark Benavidez at (818) 677-3901.