Police found Lawrence Adamczyk in the bleachers at Riverside Brookfield High School.
He later admitted to masturbating while watching the swim meet and said a brainwave message from Bieber had directed him there.
"This individual is obviously disturbed. Hopefully the guy can get some help, but either way, the children are safe, the children are protected. But, I mean, there are those outliers that you can't control."
The police chief says Adamczyk was planning on trying to find a young boy at the high school to victimize.
He was on parole and has a prior record of sex offenses but was not a registered sex offender.
He was charged with one count of criminal trespass and one count of disorderly conduct.