First of all Virgil has been on the top of my list for a very long time. RJ needs to be an older person most likely a man. Rj has been killing for a long time and has influenced and mentored many people.
Virgil had a full time job where he was able to meet Jane and shake his hand, as well he was able to control evidence and events in his favor. Either Jane was getting to close to finding out who Virgil was or Virgil simply got bored he needed to change things up.
Virgil retired as head of the CBI. This enabled him to devote more time to being RJ. Over the years many people have seen RJ and know who he was. They just would never betray him. Virgil needed to change things up. In his leave he was able to tie up loose ends.
Now Virgil was able to completely change things up. He had massive reconstructive surgery including voice alterations. Introducing Red John formerly known as Virgil Minelli now known as Kirkland.
Kirkland needed to talk to Jason, because they were close friends. When he asked one of his closest friends(Jason) if he had ever seen him before or if he reconized him it was to confirm that his makeover was successful.
After he received confirmation, he killed him quickly and almost painlessly. Kirkland said that if he was ever in this position he would hope there would be a friend to do the same for him.
Kirkland and Virgil Minelli are the same guy Red John
