 SOURCES TELL US THE FIREARM HE USED WAS LEGALLY PURCHASED BY AND REGISTERED TO HIS FATHER. THE SUSPECT WAS ALSO WEARING A T-SHIRT WITH THE LOGO OF A POPULAR GUN-RELATED YOUTUBE CHANNEL ON IT. CBS'S NORA DANO WITH MORE. CBS NEWS HAS LEARNED ONE LOCAL POLICE OFFICER EVEN ENCOUNTERED THE GUNMAN, BUT WAS FORCED BACK WHEN THE SHOOTER POINTED HIS WEAPON AT HIM.