A source told Action News on Thursday morning that 29-year-old Garrett Reid died from an accidental heroin overdose.
That information was confirmed at an afternoon news conference by Northampton County District Attorney John Morganelli and Northampton County Coroner Zachary Lysek.
Garrett Reid was found dead in his dorm room on Aug. 5 at Lehigh University in Easton, where he was assisting the team's strength and conditioning coach during training camp.
At Thursday's news conference Morganelli said from the start of the investigation, investigators found no signs of foul play. He said Reid was found alone in his room, slumped over in a chair with heroin paraphernalia nearby.
Lysek said toxicology tests confirmed that the cause of death was an overdose of heroin, and that all evidence pointed to the fact that the overdose was accidental.
Morganelli said that investigators found 47 syringes and 65 needles in Reid's gym bag, many of them unopened.
Also found were syringes and spoons.
"We are confident today that Mr. Reid's death was the result of a self-injected lethal dose of heroin," he said.
Morganelli said the investigation is now examining from whom Garrett Reid got the narcotics and the drug paraphernalia.
He also said that besides the heroin, investigators found 19 vials of an unknown liquid, but did not say what they contained.
"We're not sure, exactly, what those substances are at this time," he said, adding they were also in the bag but had nothing to do with Garrett Reid's death.
Morganelli said Eagles head coach Andy Reid and other members of the Eagles staff have been cooperating fully with investigators. In a written statement issued by the Eagles, the Reid family said:
"These results sadly confirmed what we had expected all along. We understood that Garrett's long-standing battle with addiction was going to be difficult. He will, however, always have our family's love and respect for the courage he showed in trying to overcome it. In the end, we take comfort in our faith and know that he's in a better place. We miss Garrett. We miss his smile, his laugh, and his energy and we will forever love him.
"There are many other individuals and families engaged in this struggle in their own lives, and they will always have our support, encouragement, and understanding. Never give up!"
Garrett Reid's addiction first became public in 2007 when he admitted he was high on heroin when he ran a red light while driving his Jeep and rammed a car.
For Garrett and his family there came a series of arrests and re-arrests for probation violations, and the smuggling of drugs into his jail cell.
Five years ago in court, Garrett Reid told a judge "I don't want to die doing drugs. I don't want to be that kid who was the son of the head coach of the Eagles, who was spoiled and on drugs and OD'ed and just faded into oblivion."
Shortly after Garrett's death, Andy Reid indicated that his son may have had a relapse.
Some 900 people attended Garrett Reid's funeral.
The mourners included notable names from the Eagles and the across the NFL, including quarterback Michael Vick, former quarterback Ron Jaworski, NFL Commissioner Roger Goodell and Patriots head coach Bill Belichick.