Video shot by ABC7 viewer John Adamo showed that someone chopped away at the wood near the base of the cross, which sits atop Mount McCoy. The damage was estimated at about $2,000.
The Rancho Simi Recreation and Park District immediately began repairs.
The cross is owned by the Simi Valley Historical Society and is surrounded by land owned by the park district.
Anyone with information about this case was asked to contact the Simi Valley Police Department at (805) 583-6950.