Nigerian police , soldiers accused of killing 133 during riots in November 2008 . Comment: Witnesses say police units summarily executed unarmed men and boys . HRW says death toll could be `` substantially higher '' than documented cases suggest .
Nigerian police , soldiers accused of killing 133 during riots in November 2008 . U.S.-based Human Rights Watch says main victims were young Muslim men . Witnesses say police units summarily executed unarmed men and boys . HRW says death toll could be `` substantially higher '' than documented cases suggest .