A 15-year-old died Friday when the power went out in his East Boston home and his ventilator failed, according to Boston Police.

Fernando Vargas was found dead in a public housing complex where his family lives. Fernando suffered from multiple disabilities, including cerebral palsy, mental retardation and seizure disorder, local station WCVB reported.

At 5 a.m., an alarm sounded on his ventilator. His family went in his room to check on him, and they switched the power source of the ventilator to a backup battery pack. Once family members saw that the pack was working, they returned to bed.

One hour later, a personal care attendant, who stays with the family, went in to give Fernando medicine and found the teen dead.

Investigators are trying to determine if the backup battery pack failed or if the teen died of natural causes.

Caroline Allen, of NStar, said the power went off at 4:50 a.m. and came back on at 6:47 a.m. She said that the cause of the power outage was a cable failure.