Story highlights Coach Andy Reid's son Garrett died of an accidental heroin overdose, coroner says

The district attorney says Garrett Reid injected himself with the fatal dose

Garrett Reid had a long history of drug problems

An accidental heroin overdose killed the son of Philadelphia Eagles head football coach Andy Reid, the coroner of Northampton County, Pennsylvania, said Thursday.

Garrett Reid, 29, was found dead in his room at the Eagles training camp at Lehigh University, in Bethlehem on August 5. He had been assisting the team's strength and conditioning staff at training camp as a guest of his father, the team said in August.

''We are confident today that Mr. Reid's death was the result of a self-injected lethal dose of heroin,'' Northampton County District Attorney John Morganelli told reporters in Easton. He cited the autopsy and toxicology results as well as syringes and needles found by investigators when they found the body.

Morganelli said his team was trying to determine who provided Reid with his illegal drugs and/or paraphernalia.

The younger Reid had an extensive, documented history of drug use, rehab stints, and trouble with the law. But he also had "bold laughter and zest for life" and was "proud of his rank as an Eagle Scout," according to an online statement posted by the Frank C. Videon Funeral Home in Philadelphia before the August 7 funeral.