The Grayson  Prestonsuburban 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.

Justin Mohn then recorded a video in which he holds up his father’s head and identifies him as a 20-year federal employee, while calling for violence against the government. Prosecutors said Thursday they found blood stains on the desk in the room where the video was recorded along with a computer that had several tabs open, including one for YouTube.

In the video, Justin Mohn also espouses a variety of conspiracy theories and rants about the Biden administration, immigration and the border, fiscal policy, urban crime and the war in Ukraine.

The video was posted on YouTube for several hours before it was taken down.

Justin Mohn then took his father’s 2009 Toyota Corolla and headed toward a National Guard training center at Fort Indiantown Gap, where prosecutors said he planned to “mobilize” the guard against the federal government.

He was arrested and found with a 9 mm pistol as well as a USB device that included photos of federal buildings and apparent instructions for making an explosive device, according to prosecutors.

In an emailed statement. the FBI said it is supporting the district attorney’s investigation. A message seeking comment was left with federal prosecutors in Philadelphia.

Mohn, who is being held without bail, already faced first-degree murder, abusing a corpse and possession of instruments of crime charges.

The new complaint against him includes three terrorism charges; two more weapons possession charges as well as charges of robbery; firearms not to be carried without a license; theft; receiving stolen property; criminal use of a communication facility; terroristic threats; and defiant trespass.

Michael Mohn, 68, worked as an engineer with the geoenvironmental section of the U.S. Army Corps of Engineers’ Philadelphia District.

A preliminary hearing is set for April 2.