An armed private security guard has been arrested after shooting an 88-year-old woman in her own Encino home after he mistook her for a burglar on New Year’s Eve, according to officials and the guard’s attorney.

The specifics of the incident were not immediately released by the Los Angeles Police Department or the guard’s employer, ACS Security, a Los Angeles-based armed-response private security company.

Police said the woman was shot once in the torso at her home on Encino Avenue around 8:30 p.m. on New Year’s Eve by an ACS Security guard who was responding to a burglary alarm. ACS confirmed the guard was patrolling alone. The woman was taken to a hospital in stable condition.