HARTFORD, Conn. (AP) The parents of one of the 20 children killed in the Newtown, Connecticut, school shooting are asking Facebook founder Mark Zuckerberg to remove hateful and harassing comments posted by conspiracy theorists who say the shooting never happened.

Leonard Pozner and Veronique De La Rosa wrote Zuckerberg a letter published Wednesday in The Guardian. Their 6-year-old son, Noah, died in the December 2012 Sandy Hook Elementary School shooting, which also claimed the lives of six educators.

Pozner and De La Rosa say Facebook should prohibit posts by conspiracy theorists who have been harassing and threatening them and relatives of other mass shooting victims.

A Facebook spokeswoman says the company acknowledges victims are vulnerable to offensive comments but it doesn't allow users to mock, harass or bully tragedy victims.