The body of T G Rimpoche was found hanging from the ceiling fan at about 1 am yesterday by his sister.
Police was immediately informed and the body was later sent for post mortem.
In a suicide note recovered from a diary in the room, Rimpoche has mentioned that he has committed many sins and that God would not forgive him, police said.
It is, however, suspected that he was depressed over the defeat of a close relative in the recent Arunachal Pradesh Assembly elections. Senior police officers chose not to disclose the name of that relative.
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Rimpoche is said to be known to Dalai Lama, the Tibetan spiritual leader, and has a political background in Arunachal Pradesh.
He had arrived at Delhi from his state on May 2 and was staying at his sister's place. His family has told police that Rimpoche kept silent the whole of Friday and stayed alone in his room after hearing about the defeat of his relative. They, however, are not sure if that contributed to the cause of his extreme step.