In this video, shot in a Philadelphia hotel room in 1999, then-FBI agent Robert K. Wittman (in suit and tie) goes undercover against a Civil War collector from Kansas City who is trying to sell a stolen relic of African-American history, the battleflag carried by one of the U.S. Army’s first black regiments. The story of this sting is the subject of a chapter in Wittman's new memoir, Priceless. (Video obtained by The Philadelphia Inquirer).