A 20-year-old college student pleaded guilty Tuesday to one count of illegally selling homemade “ghost guns" with no serial numbers, along with other guns and devices which convert guns into automatic weapons.

David Sungur was a full-time student at George Mason University, prosecutors said in a statement of facts filed Tuesday, and lived with his family in Fairfax City. The government said Sungur began buying guns in January 2019 and soon began selling and making them until his arrest in March of this year. Sungur admitted in the statement of facts that he advertised pistols with no serial numbers and charged more for them because they couldn’t be linked to criminal activities. In four meetings with Fairfax County police undercover officers, Sungur allegedly sold three homemade pistols, two rifles and eight commercially made handguns for nearly $7,000, according to court records.

Prosecutors charged Sungur with one count of selling guns without a license, so he faces a maximum sentence of five years when he appears again before U.S. District Judge Anthony Trenga on Dec. 16.