Police have charged a 15-year-old Rockville boy with rape after they say he threatened a neighbor with a knife and sexually assaulted her.
Montgomery County Police said Saturday the teen is being charged as an adult with first-degree rape, first-degree assault and home invasion.
Police say he entered the victim's home through an unlocked door and sexually assaulted her when she returned home from grocery shopping late Thursday night.
Police say he grabbed her from behind and threatened her with a knife when she walked into her bathroom.
The attacker was wearing a mask, but police say they reviewed surveillance video that showed the attacker running from the area of the victim's home on First Street in Rockville to his own home, also on First Street.
Police say the teen admitted his guilt in a police interview. He is being held without bond.