Australia’s worst mass murderer Martin Bryant was driven to kill over his hatred of an elderly couple who refused to sell his family a bed and breakfast, leaked psychiatric reports reveal.

The admissions came from the notes of forensic psychiatrist Paul Mullen, who interviewed Bryant for more than four hours in the days after the April 1996 Port Arthur massacre.

Bryant, who killed 35 people, first shot Noelene and David Martin at their Seascape Cottage bed and breakfast, and said he had worked on the plan to kill the couple for more than 12 months.

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According to The Daily Telegraph, Dr Mullen said Bryant spoke of the couple’s refusal to sell the business to his father, Maurice, after years of attempts, and blamed them for his father’s suicide and the downfall of his family.

Bryant told Dr Mullen the Martins were “very mean people” and “the worst people in my life”.

“It was set in my mind, it was just set that Sunday,” Bryant said, according the psychiatrist’s notes.

“I wasn’t worried about losing my property or never seeing my girlfriend again. It was just in my mind to go down and kill the Martins and a lot of people.”

Dr Mullen reported Bryant chose the Port Arthur tourist site because “a lot of violence has happened there, it must be the most violent place in Australia, it seemed like the right place”.

“He went to Port Arthur with the intention of killing, and being killed,” Dr Mullen said.

“He acknowledged that he had thought about how to do it and had intended to end his life by either being shot down or by blowing himself up.”

The plan escalated to a massacre as Bryant reported feelings of intense loneliness, telling Dr Mullen he was angry at people who were unkind to him after the incident : “All I wanted was for people to like me.”

Dr Mullen said: “He talked of the extent to which he thinks about the distress and rejections in the past. He said that he tries to live day by day, but acknowledged frequent thoughts about past rejections and what he recalls as victimisation at school by bullies intrude.”

According to his interview, Bryant feared he had no future in his late 20s, had difficulty sleeping because he thought his house was haunted by two women and had become a day drinker.

Bryant — who is now 58 and reportedly has an IQ of 66 and a limited vocabulary — was given 35 consecutive life sentences, serving them in Hobart’s Risdon Prison.

The revelations mark the first concrete details of Bryant’s motives, which have been the subject of conspiracy theories following the incident.

The shooting — Australia’s worst — drove then-prime minister John Howard to pursue significant firearms reform, including a national ban on rapid-fire guns and a government buyback.