Johnson, 30, of Sterling, was found dead from five gunshot wounds in his SUV parked at the intersection of Trail Run and Great Trail terraces Dec. 27, 2012. The incident marked Loudoun County's sole homicide in 2012.
The prosecution's case relied heavily on the testimony of Linsey Hardwick, Williams' then-girlfriend. Following the incident, Hardwick drove Williams to Delaware to dispose of the weapons and later traveled to Colonial Beach, where Williams was ultimately arrested Feb. 12, 2013.
Hardwick pleaded guilty to a lesser sentence of accessory to murder after the fact in September. Her sentencing is scheduled for June 27.
Judge Thomas Horne is scheduled to sentence Williams Sept. 19 at 4 p.m. Jurors recommended Williams spend life in prison.