Cornyn said he’d soon introduce the Stop the Sale of Murderabilia Act, which would stop prisoners from mailing or having another person mail any object the prisoner intended to sell.

Cornyn was prompted to draft the legislation after reports that a letter from Nidal Hassan is being sold online. Hassan, an Army Major and psychiatrist, was recently convicted of the mass shooting at Fort Hood in Texas, where he killed 13 people and wounded 30 more.

“A letter penned by convicted Fort Hood terrorist Nidal Hasan in prison was posted for sale online,” Cornyn said. “While it has not yet been determined if Hasan deliberately attempted to profit off the sale of his letter, items like these are being sold by convicted serial killers and other criminals on a daily basis.”

Some states have attempted to ban the sale of “murderabilia,” but Cornyn said a federal law was needed.