Where can I find the Tripitaka source of the Death of Ven. Moggallana? The part of him being beaten by thugs and then came to the Buddha to take permission to go into parinibbana.
My impression is this story is not from the suttas.
According to the Commentaries (J.v.125ff) his death resulted from a plot of the Niganthas. Moggallāna used to visit various worlds and return with his report that he had discovered that those who followed the Buddha's teaching reached happy worlds, while the followers of the heretics were reborn in woeful conditions. These statements diminished the number of the heretics and they bribed brigands to kill Moggallāna. They surrounded the Elder's cell in Kālasilā, but he, aware of their intentions, escaped through the keyhole. On six successive days this happened; on the seventh, they caught him and beat him, crushing his bones and leaving him for dead. Having recovered consciousness, with a great effort of will, he dragged himself to the Buddha in order to take his leave, and there he died, to the sorrow of the deva worlds. This sad death is said to have been the result of a sin committed by him in a previous birth. Acting on the instigation of his wife, he had taken his blind parents into a forest, where, pretending that they were attacked by thieves, he had beaten them to death. For this deed he suffered in hell for innumerable years, and in his last birth lost his life by violence.
The account in DhA.iii.65ff. differs in several details. The thieves tried for two months before succeeding in their plot and, in the story of the past, when the blind parents were being beaten, they cried out to the supposed thieves to spare their son. Moggallāna, very touched by this, did not kill them. Before passing into Nibbāna, he preached to the Buddha, at his request, and performed many miracles, returning to Kālasilā to die. According to the Jātaka account his cremation was performed with much honour, and the Buddha had the relics collected and a Thūpa erected in Veluvana.