Madison police chief: Authorities investigating how 15-year-old school shooter obtained gun

Police in Madison, Wis., are investigating how the 15-year-old school shooter obtained a handgun.

Police Chief Shon Barnes, in an interview Tuesday morning with CNN’s John Berman, said partners at the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) are expediting a trace form “to determine the origin of that weapon, who purchased it, and how it got from a manufacturer all the way into the hands of a 15-year-old girl.”

“These are questions that’s going to take some time to answer,” Barnes continued.