Northampton County coroner Zachary Lysek said a toxicology test confirmed the presence of heroin in Garrett Reid's body. Investigators revealed they found a used syringe and spoon in Reid's room, along with a gym bag filled with dozens of syringes and needles, many of them unopened.
"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 said at a news conference in Easton.
"The autopsy and toxicology is consistent with that conclusion," Morganelli added, "and it is consistent with the evidence of the syringe and other drug paraphenalia that we determined was consistent with heroin use."
County coroner Zachary Lysek said the autopsy found Reid had "acute opiate toxicity" and that his death was accidental.
Reid was found dead in his dorm room early on Aug. 5 at Lehigh University in Bethlehem, Pa., where he was assisting the Eagles' strength and conditioning coach during training camp. He was a recovering drug addict who seemingly had turned around his life. His father, Andy Reid, had indicated his 29-year-old son might have had a relapse.
In a statement released through the Eagles, the Reid family said Garrett Reid's smile, laugh and energy will be missed.
"These results sadly confirmed what we had expected all along," the family's statement said. "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."
The Reid family also sent encouragement to other families dealing with addiction.
"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," the family said. "Never give up!"
Morganelli said the investigation now is focused on learning the identity of Garrett Reid's supplier. Investigators are combing through Reid's phone records to see who he was calling and texting in the days, weeks and months leading up to his death. Reid's body showed signs of chronic drug use, according to Lysek.
The Associated Press contributed to this report.