Hours before Gov. John Hickenlooper, surrounded by family members of victims of shootings in Aurora and Littleton, signed a package of contentious gun control bills, Colorado's top prison official was shot and killed in front of his home. Tom Clements, 58, had been appointed executive director of Colorado Prisons in January 2011, and had won praise from officials and activists for his commitment to reform; Tuesday night at around 8:30, he answered his front door and was killed by an unknown gunman. Police have no suspects, but prisons have been placed on a partial lock-down and security has been increased at the state capitol and the governor's mansion. In an emotional press conference, Hickenlooper called Clements' murder "an act of intimidation." Hours later, the governor signed a series of new laws requiring background checks for private gun sales and banning magazines with more than 15 rounds, the end result of a long and emotional process. "I started crying," Tom Mauser—whose son was killed at Columbine High in 1999—told The New York Times. [Denver Post | Denver CBS | NYT]