The alleged assassin of conservative Christian activist Charlie Kirk has been arrested, President Donald J. Trump said Friday morning. Law enforcement sources told the New York Post that Tyler Robinson, 22, a Utah resident, is in custody. Kirk, 31, was shot and killed during a Sept. 10 public appearance at Utah Valley University (UVU) in Orem, Utah. He had just begun speaking to several thousand students gathered in an outdoor courtyard when a gunman atop a building 200 yards away opened fire.