U.S. federal courts have imposed 18-month prison sentences on two American citizens for running laptop farms and helping North Korean information technology (IT) workers generate over $1.2 million in revenue for Pyongyang’s weapons programs.

The Department of Justice (DOJ) announced the sentences in two separate cases involving Matthew Issac Knoot of Nashville, Tenn., and Erick Ntekereze Prince of New York on Wednesday, according to a press release.

The men “received and hosted” laptops in their homes that “victim U.S. companies shipped to IT workers they had hired and who the victim companies believed were located at the defendants’ residences,”