Philadelphia firefighter Gabriel Lee, who died during a night shift in North Philadelphia in July, succumbed to heart disease, the Medical Examiner's Office said Wednesday.

Lee, 42, a 17-year veteran of the department, died July 23 after being found unresponsive in the basement of the Ladder 12 firehouse, 1325 W. Cambria St.

Fire Commissioner Adam Thiel said Lee had been responding to calls earlier in his shift. Frank Keel, spokesman for Local 22 of the firefighters union, said firefighters attempted to resuscitate him but were unsuccessful.

Lee was taken to Temple University Hospital, where he was pronounced dead. Hundreds of firefighters and police gathered outside the hospital that night.

An East Germantown resident who was married and had three children, Lee was also an accomplished amateur boxer and a respected firefighter, his family and department officials said. In 2001, Lee was named a winner of the Local 22 Distinguished Service Award.