A Northern Virginia man known for threatening the creators of “South Park” is scheduled to plead guilty Wednesday afternoon to aiding the Somali terrorist group al-Shabaab.

A plea agreement hearing for Zachary A. Chesser, 20, is set to take place in federal court in Alexandria. According to court records, the Bristown resident told federal agents that he tried to go to Somalia twice to join al-Shabaab as a fighter. Authorities say Chesser once attempted to board a plane with his infant son in order to avoid detection.