Peyton Manning hired two private investigators who visited the house of the key source's parents in an Al Jazeera documentary that implicated the star and other athletes in obtaining performance-enhancing drugs, according to a report from The Washington Post.
According to The Washington Post story, the pair visited the Austin home of Charlie Sly's parents five days before the report came out.
In December, Al Jazeera aired a documentary that included Sly - an intern at an Indianapolis anti-aging clinic - suggesting Manning's wife received deliveries of human growth hormone at the Manning's home in 2011, the same time period when Manning was rehabbing from neck surgeries.