Brookwood Hall, an Islip Town-owned mansion and historic site, was broken into and robbed last week, police said.
The thief pried open a door on Thursday around 12:30 p.m. and made off with electronics, including three televisions, a computer and an iPod, Suffolk police said Tuesday.
The hall in East Islip houses several Islip Town offices, including parks and recreation, as well as the Islip Art Museum and the nonprofit Islip Arts Council.
“It’s under investigation, so we cannot comment,” town spokeswoman Caroline Smith said.
Police declined to release the estimated value of the stolen items.
The three-story, 41-room mansion was built in 1903 for the affluent Knapp family and was sold in 1929 to financier Francis B. Thorne. It later became an orphanage until the town purchased the property in 1967.