I dont know if this was already solved but its stopping me from continuing the main story.

On Tactical Thinking you are given a mission to wipe out the Rail Road HQ, thats including Deacon. Once wiping everyone out you end up at the main part the hq and PAM is in the other room. A marker was still appearing to kill Deacon. I went back to where you first enter the building and Deacon was laying on the floor dead but still has a marker above him saying to kill him. I dont know what to do from here and I cant continue without having him gone. Please help!!! :"(