In his new book Rock Roadie, Wright claims that Jeffrey told him he plied Hendrix with pills and alcohol in order to kill him and claim on the guitarist's life insurance.
Hendrix died in September 1970. His body was found in a room at London's Samarkand Hotel booked by Monika Dannemann, whom Hendrix had known for a matter of days.
Jeffrey allegedly made the confession to Wright in 1971, two years before he was killed in a plane crash.
Writing of the admission, Wright says: "I can still hear that conversation, see the man I'd known for so much of my life, his face pale, hand clutching at his glass in sudden rage."
Jeffrey is quoted by Wright as telling him: "I was in London the night of Jimi's death and together with some old friends.. we went 'round to Monika's hotel room, got a handful of pills and stuffed them into his mouth...then poured a few bottles of red wine deep into his windpipe."
The manager was allegedly worried that Hendrix was about to sack him. He had recently taken out a life insurance policy worth $2 million, with Jeffrey as beneficiary, reports Britain's Mail On Sunday.