The FBI received a complaint that Lionel Nelson Williams had been posting ISIS propaganda on Facebook and had recently acquired an AK-47 assault rifle. An FBI inquiry into Virginia firearms sales data revealed that Williams had purchased the AK-47 from an online dealer the day after the San Bernardino shootings. Undercover FBI employees, posing as ISIS members, began to correspond with Williams online. Williams provided one of the undercover employees with account information to access $200 from a prepaid cash card. When Williams was arrested, FBI agents found in his possession a semi-automatic handgun and the AK-47 rifle.