A staffer at a Brooklyn charter school received an e-mail demanding she send nude photos and pornographic video of herself — or else students would be harmed, police said Tuesday.

The Friday e-mail said students at the Brooklyn Urban Charter School in Windsor Terrace would be hurt Monday if the 29-year-old staffer didn’t comply.

Police initially determined that the email had come from a student, but further investigation revealed the boy’s account was hacked by somebody in California, sources said.

The staffer never sent any photos or video and no students were harmed.

It wasn’t immediately clear if cops knew who made the threat.