I have a feeling that John later added in the verses following John 20:18 (the encounter with the Disciples) in order to debunk those we read about in the Epistle’s, who were saying Jesus did not come in the flesh. I also draw this conclusion based on the contradiction between John 20:22 and John 16:7. Moreover I often wonder why Jesus told Mary to inform the disciples that he is ascending, yet he then visits them later on himself… then it appears he still has not left over a week later.

Is there evidence that perhaps a second author authored the latter half of John 20 (writing style or language for example)?