Here's the full statement released by the league:
Former FBI Director Robert S. Mueller III will conduct an independent investigation into the NFL's pursuit and handling of evidence in the Ray Rice domestic violence incident, Commissioner Roger Goodell announced tonight. Director Mueller's investigation will be overseen by NFL owners John Mara of the New York Giants and Art Rooney of the Pittsburgh Steelers, and the final report will be made public.
Mara and Rooney are both attorneys. Commissioner Goodell pledged that Director Mueller will have the full cooperation of NFL personnel and access to all NFL records. Mueller served as director of the FBI for 12 years (2001-2013) under two presidents. He is currently a partner in the law firm of WilmerHale and is based in Washington, DC.
As we agree, and acknowledge, that getting to the bottom of this incident is exponentially more important than the result of tonight's football game (or any game).