Agent Darius Barnes was sent by Julian Dawes to investigate Marcus Boone who was known to be an associate of Nick Mendoza. Upon finding Boomer, the intention was to be led to Nick where Agent Barnes could then arrest him and bring him back to Dawes.
Holding Boomer's dossier in his possession, Barnes started his investigation at Tony Alpert's compound where Boomer had lived for a few years after going AWOL from the Army. Aware of Alpert's stance on the government, he parked his government vehicle away from the compound in order to avoid suspicion. Despite that, Barnes' cover was quickly blown and he was captured by Alpert who feared Barnes would spread the word about his intention to start a civil war to the federal government. As a result, Barnes was brutally tortured and subsequently burned alive inside an abandoned house before being buried in a shallow grave soon afterward. After discovering this, Nick Mendoza payed his respects and stated that he would call the FBI tip line and inform them of the events that lead to Agent Barnes' death.
- Upon finding his grave, Nick can bend down and "Pay Respects". This is a reference to a scene in Call of Duty: Advanced Warfare, when the player is prompted to press the button to "pay respects" to a fallen Marine at his funeral.