The suburban Philadelphia man charged with decapitating his father and posting a video online in which he held up the severed head had a device with photos of federal buildings and apparent instructions for making explosives when he was arrested, authorities said Thursday.

Justin Mohn, 32, faces a dozen new charges, including terrorism and theft, in the death last month of his father Michael Mohn, the Bucks County District Attorney’s office said Thursday.

A woman who answered the phone at the Bucks County Public Defender’s office, listed as Mohn’s attorney, declined to comment on Thursday.

According to prosecutors, Justin Mohn fatally shot his father with a pistol he bought the day before and then used a kitchen knife and machete to decapitate Michael Mohn at the Levittown house where they both lived.