Updated

A stolen photo of Jamie Lynn Spears breast feeding her baby girl has sparked a federal pornography investigation, TMZ reports.

Federal and local authorities are looking for someone peddling 12 photos of Jamie Lynn, her older sister Britney Spears, her infant daughter Maddie and the baby's father Casey Aldridge, law enforcement sources told the Web site.

One of the pictures shows Jamie Lynn breast feeding Maddie, and the 17-year-old's left breast is exposed, TMZ reports, adding that the photos were taken on Aldridge's digital camera.

Aldridge took the camera card to his local Wal-Mart in Louisiana for copies, and law enforcement believes someone at the Wal-Mart may have made extra copies, then tried to sell them, sources told TMZ.

Because Jamie Lynn is a minor, selling the photos — or buying them — could constitute a violation of federal laws prohibiting pornography. Peddling pictures of a minor's breast — even if not taken for sexual purposes, could land the seller and buyer in federal prison if they are marketed across state lines for the purpose of being lurid, according to TMZ.

Jamie Lynn Spears starred in the television series "Zoey 101" and won a Nickelodeon Kids' Choice Award for Favorite TV actress in 2006.

Click here for the TMZ report