The 12-year-olds were on the swings Sunday when a man in his 20s with a knife came up to them. One boy ran for help as the man dragged the other boy off a swing.
Police say the suspect then ordered the boy to take off his pants. Because of that, it was thought to be a sex crime.
The boy grabbed some wood chips on the ground, threw them in the suspect's face and got away.
Police say another recent incident indicates the suspect is an older boy bullying younger kids for money.
Anyone with more information is urged to call Orange County Crime Stoppers at (855) TIP-OCCS.