Two boys, ages 11 and 14, have been charged with breaking into the home of a 60-year-old woman and trying to sexually assault her, police said Tuesday.

The boys wore bandanas and gloves when they broke through a window in July, and one of them tried to sexually assault her but stopped when a heart device was triggered, Detective Scott Stanfield said.

The boys were charged with burglary with intent to commit sexual assault. The boys had a kit that included items to restrain the victim, Stanfield said.

A 15-year-old girl and a 16-year-old boy were standing outside the victim's house serving as lookouts, Stanfield said, but they have not been charged because they did not break into the house.

Police said they do not know a motive for the attack. No one was arrested until someone who had seen a suspect near the woman's house contacted police, Stanfield told the Austin American-Statesman.

The boys have been released from a juvenile detention center on the condition that they wear electronic monitoring devices, Stanfield said.