RALEIGH, N.C. — Two people pleaded guilty Thursday to federal charges that they plotted to behead witnesses from a terrorism trial involving several Triangle men.

Nevine Aly Elshiekh, 47, and Shkumbin Sherifi, 22, each pleaded guilty to conspiracy to commit murder for hire. They are scheduled to be sentenced in February, when they face up to 10 years in prison.

Elshiekh and Sherifi were arrested in January after an FBI sting in which Sherifi's brother, Hysen Sherifi, allegedly tried to have three witnesses in his October 2011 federal terrorism trial killed.

Hysen Sherifi, 27, was sentenced in January to 45 years in prison for plotting to attack the U.S. Marine Corps base in Quantico, Va., as well as targets overseas. Six other men also are serving federal prison sentences for their roles in the terror cell.

Court records show that an FBI informant posing as a hit man accepted a $750 down payment on a killing from Elshiekh, who also provided the informant with the names of the people to be killed.

Shkumbin Sherifi later paid the informant $4,250 for the first killing, and the informant showed him doctored photos that appeared to show a beheaded corpse in a shallow grave as a way of confirming that he had killed a witness, according to court records.

Defense attorneys for Elshiekh, a former special education teacher at Sterling Montessori Academy and Charter School in Morrisville, had maintained that she was a pawn in the alleged plot.

She struck up a relationship with Hysen Sherifi after his trial, which she attended because she is a family friend of Omar Hassan, another member of the terror cell who was tried along with Sherifi.

Her attorneys said she was just a courier who passed along information from Hysen Sherifi and

never knew that he wanted people beheaded.

Aly Elshiekh, a retired North Carolina State University professor, declined to comment on his daughter's plea, saying only that he believes in the U.S. justice system.

Defense attorney James Payne said pleading guilty was difficult for Shkumbin Sherifi.

"He was ready and willing to come forward and do the right thing," Payne said.

As part of their plea agreements, Elshiekh and Shkumbin Sherifi could testify against Hysen Sherifi when his trial begins next week.