A playground in Mystic, Connecticut, dedicated to a girl shot during the Newtown massacre, is allegedly being vandalized by "truthers" who claim the shooting never took place.

A vinyl sign weighing 50 pounds was stolen last Tuesday from the Grace McDonnell Playground.

The sign featured a peace symbol that was based on the 7-year-old girl's drawing. She is one of the 20 children shot by Adam Lanza at Sandy Hook Elementary in Newtown, Connecticut on Dec. 14, 2012.

Grace's mother, Lynn McDonnell, found out about the theft when a man claiming to have stolen the sign called her.

During a brief conversation, the sign-stealer allegedly told McDonnell that he took the sign because he believes the school shooting was a hoax, CBS2.com reports.

He also taunted her that her daughter never existed, a comment that suggested he thought McDonnell was part of the alleged conspiracy.

Adam Lanza fatally shot 20 children and six adult staff members at the elementary school after killing his mother at their nearby home, in one of the most infamous shootings in recent history.

However, a small group of "truthers" allege the shooting never occurred or was part of a ‘false flag’ operation designed to open the door to the confiscation of all guns by the government, The Raw Story reports.

Truthers offer numerous theories about what they say really happened, but all of them can be easily explained or debunked.

The Grace McDonnell Playground was opened on April 27, and is one of 26 being built in Connecticut, New York and New Jersey by the Where Angels Play Foundation, to honor the victims of the massacre.

The foundation has ordered a replacement sign, according to executive director MaryKate Lavin.

"We are going to keep moving forward," she told NBC Connecticut. "This is not going to stop us, but it is heartbreaking."

The sign theft at the Grace McDonnell Playground isn't an isolated event. It comes just days after vandals painted graffiti at a playground in Hartford dedicated to Newtown victim Anna Grace Marquez-Greene.

The sign was spray-painted with the letters “BEKS” with a peace sign and then the words “To Sandy Hook,” CBS Connecticut reports.