Three brothers aged 8, 11 and 12 and their 12-year-old friend were questioned by police investigating an alleged sexual assault on three young boys in a park in England.

The three older boys were arrested Tuesday and released on bail, but the youngest child was let go without further action because he is underage.

At least one of the victims was allegedly forced to strip and was smeared with dog feces while his friends were ordered to perform indecent acts on him. The incident may have been a copycat attack inspired by the conviction of two young brothers for a similar assault in England earlier this month.

The father of one of the three victims, who were all ten years old, told The Sun newspaper that his son had been traumatized by the assault.

“My lad was happy and now he is withdrawn," the father said. "What has happened is unforgivable."

Click here for more on this story from the Times of London.