One witness complained that the security was concerned about food and beverages being brought into the theater, but did not catch Loibl's guns.
Sounds about right.
Also, the issue of obsessive fans is currently being highlighted by the plight of Chappel Roan, who now seems uncomfortable with the level of fame that she'd previously strived for.
After her performance ended at 10:00 p.m. local time, Grimmie signed autographs inside the venue. At 10:24 p.m., she was approached by 27-year-old Kevin James Loibl. She opened her arms to hug him. Loibl then pulled out his Glock pistol and shot her three times at point-blank range.