The report examined Shipman's early career
Harold Shipman killed up to 15 patients in his early career, bringing his total murder toll to an estimated 250 people, the Shipman Inquiry has revealed.
Chairman of the inquiry Dame Janet Smith said Shipman unlawfully killed three men at Pontefract General Infirmary (PGI) in the 1970s.
Dame Janet said the probable number the former Hyde GP killed at the hospital was "between 10 and 15 patients".
She said between 1971 and 1998, Shipman killed an estimated 250 people.
Dame Janet decided to investigate Shipman's time at PGI when Sandra Whitehead, who worked with him at Pontefract, contacted police following his death in prison in January 2004.
"In many cases I have been unable to reach a definite conclusion," she said.
"With this sixth report I believe that the inquiry has finally provided as complete a picture of Shipman's activity as it would be possible to give."
Dame Janet said Shipman had "unlawfully" killed Thomas Cullumbine, 54, John Brewster, 84 and James Rhodes, 71 in April and May 1972.
She added there was "quite serious suspicion" about the deaths of Louis Bastow, 72, John Auty Harrison, 70, Elizabeth Thwaites, 74 and Susan Garfitt, four - his youngest possible victim.
Dame Janet, who investigated 137 deaths at PGI, said although she was suspicious about 14 deaths they were "probably natural but there is one or more feature of the evidence that gives rise to some suspicion or unease."
In three cases, Mrs Edith Swift, 49, Mr Butterfield Hammill, 86, and Mrs Cissie MacFarlane, 57, Shipman had administered inappropriate treatment administering "dangerously large doses of a sedative drug."
Dame Janet also investigated the concerns of Georgina Francis, 62, from Hyde who contacted the inquiry saying she feared Shipman tried to kill her.
But Dame Janet's final report states she has no reason to suspect Shipman was trying to kill Mrs Francis when he gave her the painkiller diamorphine in 1996.
She also upheld two verdicts from earlier reports where she said Shipman had not killed Alfred Wright, who died aged 63 in 1987 but had killed Beatrice Clee at home in Hyde in 1989 aged 78.
The report has discounted claims from an ex-prisoner that Shipman confessed to 508 deaths when he was in HMP Preston.
Dame Janet rejected comments made by John (Jonathon) Harkin saying the figure was too high, adding: "Nor in my view can any reliance be placed on Mr Harkin's account."