After Denver Broncos quarterback Peyton Manning learned he was going to be tied to a doping scandal in an upcoming investigation by Al Jazeera, his lawyers sent two private investigators to find the key source, Charlie Sly.

Sly, who was secretly recorded by Al Jazeera, had made a slew of allegations, including some against Manning. Just before the documentary aired in December, Sly recanted everything he had said, without knowing what statements he had made.

That retraction has been the centerpiece of the defense of Manning, run by PR guru Ari Fleischer, a former spokesman for the Bush administration.

But a 911 call obtained by HuffPost sheds new light on how Sly's decision to recant his statements came about. The Washington Post first reported on the existence of the 911 call.

When two private investigators clad in black coats and turtlenecks showed up at the home of Sly's parents, his sister called 911. The men, she said, were claiming to be law enforcement, but refusing to display a badge.

Manning is preparing to play in the Super Bowl on Sunday. He has since said, through Fleischer, that medication was indeed shipped to his home, but that it was for his wife.

Fleischer has cited privacy concerns in declining to say why Manning's wife needed the substance.

Hear the full 911 call in the video above.

Watch the Al Jazeera documentary below.

CORRECTION: A previous version of this story said that Fleischer had confirmed human growth hormone had been sent to Manning's wife. Fleischer has only confirmed that medication was sent, but did not specify what kind, citing privacy concerns.