He was a convicted sex offender. Most people including those professionals would tend to believe the children. However, professionals also questioned why he would do such a thing ( apparently not his m.o.) and did the legwork to verify his alibi.
The perpetrator needs to be watched. That is a bizarre thing to do.
It says the kids urinated on the girl....which implies the rest of the kids were all boys.
Turns out that it was 3 boys and the little girl. One of the boys was her brother.
Fortunately....thanks to one of the parents of the two boys (not her brother) one of the boys told the truth.