When Muhammad Ali knocked down Sonny Liston on May 25, 1965, a 22-year-old photographer named Neil Leifer was ringside. Decades later, the image he captured still has our attention.

Sonny Liston OD'd on heroin, but it may have been ordered by the mob, according to “Pariah: The Lives and Deaths of Sonny Liston." The new doc premieres Friday on Showtime.

According to an in-depth piece from the Washington Times citing decades-old FBI documents, the Feds suspected that the 1964 fight between Muhammad Ali, then Cassius Clay, and Sonny Liston was rigged.

Clay-Liston: The Fight That Made Muhammad Ali A Half Century Ago, a Brash Youngster Named Cassius Clay Beat Sonny Liston and Started His Legend By Gordon Marino Feb. 24, 2014 11:13 pm ET Share ...

Liston’s efforts to land a clean punch against the constantly moving Cassius often were ludicrous. Officially it was an even fight at the end of six. Judge Bill Lovitt had Liston leading, 58 to 56.

Fifty years later, the AP is making available the black-and-white shot by AP photographer John Rooney of Ali standing over Liston, which won the World Press Photo award for best sports photo in 1965.

LISTON, Neil Francis - Of Fairfax, passed away peacefully at home on Tuesday, March 25th in Fairfax. Neil is survived by his loving wife Carmen Liston of Fairfax; loving father to Neil Liston, Jr ...