Traditionally it's presumed to be the Apostle John.

Yes i belive it is and if you have a few days read "The bloodline of the holy grail" it is an fasinating eye opening book.I am a catholic and i do belive there was a jesus who lived in Nazarath,however i don't belive he died on the cross and that he was the son of god. I am more sure he was a scape goat who was hung on a cross but the other theives had there leg broken Jesus did not and the "man" who we belive killed him was josph of aramathia who was his uncle who gave him snake venom mixed with vinger which made him lapse in to a coma thus making him look dead read that book !!!