Police are looking for the thief or thieves who broke into the Delaware County Historical Museum. Officials say significant artifacts were stolen from the Museum in Hopkinton either Wednesday night or early Thursday morning. They include arrowheads, vests and moccasins, and a silver tea set dating back to the 1800s. A total inventory of what was taken is still being assessed. The Historical Society is asking people to be on the lookout for anyone who might be trying to sell the stolen items.