A janitor has been arrested for alleged sexual abuse against a female coworker at a Brooklyn Elementary School.

Investigators say Kasim Khan, 32, allegedly rubbed his privates against the victim at PS 222 in Marine Park.

Parents who dropped off their kids at the school Friday said they were shocked.

"It's worrying. My kids come to this school. So it's surprising. we didn't expect anything like that to happen here," noted one parent.

Khan is being charged with forcible touching, sex abuse and harassment.