The incident occurred on a bus for Camelot Elementary School in Annandale, police said.
Jude Lovchik, 50, on trial in Fairfax County, is charged in the assaults.
The defendants face the little-used charge of lynching.
Nabra Hassanen was slain in 2017 as she walked to a Virginia mosque with friends.
Fairfax County prosecutors said in court papers that the suspect had his wife re-create the assaults.
Voters across the country are electing local prosecutors who will focus on progressive policies.
Nebiyu Ebrahim is charged in the slaying of 16-year-old Jholie Moussa.
Christopher Chimera, 39, was accused in the incident, which occurred in December 2017 and was reported in October, police said.
Duong Nguyen, 61, and his son, America, 22, were fatally shot in their Fauquier County home, authorities said.
