FBI: Gunman Planned to Kill Super Bowl Fans, Was Moments From Being Carried Out

The FBI has revealed that a threat against the Super Bowl was moments
away from being carried out. Authorities say that Kurt Havelock planned a
shooting near the stadium
Police say that Havelock was in a stadium parking lot armed with an assault
rifle and 200 rounds of ammunition before he changed his mind. According to
police, he had already mailed a manifesto to the media describing his plan.
“He could have wreaked havoc wherever he went. He could have taken out a lot of
people, a lot of civilians, innocent civilians and a lot of law enforcement and
it could have been worse than Virginia Tech, said a law enforcemnt source.
Havelock’s father said he convinced his son to turn himself in even though he
didn’t go through with the shooting.

Why did he have to turn himself in? why wasnt there any security watching in the parking lot?