Alok Mukherjee, former chair of the Toronto Police Services Board, talks to Steve Paikin about his book, "Excessive Force: Toronto's Fight to Reform City Policing." Mukherjee reflects on some of the Toronto Police Service's most challenging moments: the 2010 G20 summit protests, and the shooting of Sammy Yatim in 2013. He also discusses the bureaucratic challenges and modernization hurdles facing policing in Canada right now.