A 14-year-old boy snuck into a Vacaville home early this morning, stabbed and sexually assaulted a 13-year-old girl, and then turned the blade on the girl's 18-month-old brother when he awakened, police said.

The girl, who was stabbed more than 30 times, and her brother, who had more than 10 stab wounds, were in critical condition later in the day but were expected to survive, said police Sgt. Denise Quatman.