Denise Richards has received several threatening letters after her ex-husband, Charlie Sheen, went public last week and began waging a vendetta against the former school of their two daughters, Sam, Breaking Celebrity News is exclusively reporting.

"It was a very long weekend for Denise and the girls in the aftermath of Charlie's Twitter tirade, in which he encouraged his Twitter followers to send dog poop to Sam's former school,” a source close to Sheen told Breaking Celebrity News exclusively.

“According to Charlie's public comments, Sam was bullied, and Denise pulled both daughters out of the school last year. Denise got several threatening letters, and Charlie is telling his friends that he suspects they are from parents at the private school. Charlie and Denise live in the same gated community in Southern California, and some of their neighbors have children who go to their daughters’ former school. Several parents have told the former couple that they pulled their children from the institution because they experienced the same thing Sam did. The threatening letters are being dealt with and will be turned over to law enforcement if necessary," the insider added.