A federal jury in Raleigh, N.C. found a man already convicted in a terror plot guilty on all counts Thursday in a murder-for-hire scheme.

Hysen Sherifi, who is serving a 45-year prison sentence for his previous terrorism conviction, conspired to murder and behead witnesses who testified against him in that case.

During his incarceration at the New Hanover Detention Facility, Sherifi sought an inmate's help in hiring a hit man to target the witnesses and law enforcement officers from his 2011 trial. Others involved in the plot included Sherifi's brother, Shkumbin Sherifi, and friend, Nevine Aly Elsheikh, who pleaded guilty to their charges.

Sherifi was part of a Triangle terror cell whose members sought to wage jihad overseas and engage in military-style training. He along with the ringleader of the terrorist cell conspired to attack U.S. military personnel and their families at the Marine Corp Base in Quantico, Va.

Sherifi's conviction was applauded by Lisa Monaco, Assistant Attorney General for National Security. "Thanks to the coordinated law enforcement effort, Hysen Sherifi's jailhouse plot to behead federal agents and witnesses involved in his prior terrorism prosecution was thwarted before anyone was harmed. Today he is being held accountable for his actions," said in a Department of Justice press release.

Sherifi faces a maximum of life in prison when he is sentenced in February.