A man stole a 50-pound vinyl peace sign from a Mystic playground built in memory of a Sandy Hook shooting victim then called the slain girl's mother to tell her why he did it, according to one of the playground's supporters.

William Lavin, the organizer of the "Where Angels Play Foundation" that built the playground honoring Grace McDonnell, said Lynn McDonnell received a phone call from a man on Tuesday claiming he had stolen the sign from the playground because he believes the shooting at Sandy Hook Elementary School was a hoax. The caller told McDonnell her daughter "never existed."

The playground, which was opened on April 27, is one of 26 the foundation is building in Connecticut, New York and New Jersey to honor the victims of the Dec. 14, 2012 massacre.

Lavin says McDonnell was upset, and worried about how the theft might affect those who helped build the playground.

"The McDonnell family is the strongest and most inspiring I have come across," Lavin said

The foundation has ordered a replacement sign.

"We are going to keep moving forward," said MaryKate Lavin, executive director of the foundation. "This is not going to stop us, but it is heartbreaking."

The sign was stolen days after another playground constructed in honor of a child killed in the shooting was vandalized. Hartford police are investigating that incident.