Double murderer Kim Leanne Snibson could have killed a third time - poisoning an elderly woman to inherit her house.The Illawarra Mercury can reveal police investigated the death of Snibson's elderly neighbour Judith Palinkas in the wake of her arrest for the murders of Kathryn McKay and Greg Hosa in January 2006.Ms Palinkas officially died of bowel cancer in April 2003.However, Snibson's ex-husband Paul now suspects she may have laced Ms Palinkas' meals with dog tranquillisers to accelerate her death.Ms Palinkas changed her long-standing will on her deathbed, leaving her small A-frame house in Calymea St to Snibson after she allegedly promised to always care for her beloved dogs.Within days of Snibson moving into the house, most of the dogs were sold or put down.Ms Palinkas' sister Ailsa Woollard has confirmed the last-minute change to her sister's will and said she too had suspicions about what happened.The investigation into the 76-year-old's death was cut short as her remains were cremated, leaving no way to discover if cancer was her only killer.Mr Snibson, a soldier, claims his ex-wife had asked him about post-mortem examinations and knew there would be no autopsy on Ms Palinkas because she had a terminal illness.In a macabre twist, the house Snibson inherited from Ms Palinkas became the scene of the grisly murders of Ms McKay and Mr Hosa.Snibson and her accomplices tied up the couple and left them for hours in the house before killing them and burning their bodies.Adding weight to the suspicions are allegations raised in the NSW Supreme Court that Snibson had spent a decade planning to kidnap, assault and kill various people.During her sentencing hearings, Crown prosecutor Paul Leask aired allegations that after Snibson moved into her first home in Calymea St, she had offered a friend $30,000 to help "in seeing an old lady who lived across the road was dead".Snibson denied the allegation.Paul Snibson told the Mercury his ex-wife was a manipulative and heartless woman.He was shocked when he heard she was accused of murder but he now believed she masterminded the killings of Ms McKay and Mr Hosa and possibly hastened Ms Palinkas' death.Paul and Kim Snibson met Ms Palinkas in 2001 when they moved into a house across the road from the dog breeder.Mr Snibson said Ms Palinkas was sick for about a year before she died on April 18, 2003 and Snibson had looked after her dogs."She was there working at the kennels every day," he said."She was spending a lot of time visiting Judith and taking her grocery shopping."About four months before Ms Palinkas died, Ms Woollard saw her sister's long-standing will, which left everything to herself and her three daughters.However, Snibson told her husband that Ms Palinkas was considering changing her will and leaving her house to Snibson."Kim would tell me that she would tell Judith: 'No, no, don't worry about it'," Mr Snibson said.Ms Woollard and her family rushed from Victoria to Shoalhaven Hospital when Snibson rang to say Ms Palinkas was dying.Ms Woollard's daughter Anne reached Ms Palinkas' bedside first about 8.30pm on the night before she died."Judy had been very distressed and we knew she must've had some morphine," Ms Woollard said."(When Anne entered her room) Judy was signing something and looked a bit taken aback and asked Anne to wait outside."Mr Snibson said his wife had come home and said Ms Palinkas asked her to contact her lawyer as she wanted to change her will."Kim was a master of manipulation," he said."She told me she (told Ms Palinkas): 'No, no, just get better'."Mr Snibson said it was about 8pm when Snibson called a lawyer, who later attended the hospital with his wife. Both witnessed the execution of Ms Palinkas' new will.Ms Palinkas died the next day.Ms Woollard only learned of the new will after Ms Palinkas' funeral."We arranged to go to a solicitor in Sydney and he said nowhere does it say she was on drugs," Ms Woollard said."But the doctor had written on her (patient notes) 'TLC'."She was in shocking pain."I felt the hospital should have stopped her from making such a drastic decision when she was at the last minute like that."Usually doctors say not to make a change of plans until someone is better."A hospital spokeswoman said staff could not police visitors that patients wanted to see and caused no disruption. Because the will was drawn up by a solicitor, Ms Woollard said her lawyer could find no reason the family should question its legal validity.In court last month, Snibson denied that Ms Palinkas left her the house because she had promised to care for her precious dogs.Mr Snibson said she cared for them for the 12 months between inheriting Ms Palinkas' house and moving in.But once she moved in, she quickly got rid of most of the dogs, putting two down, keeping four and selling the rest for $4000.Mr Snibson said in the aftermath of his ex-wife's arrest for murdering Ms McKay and Mr Hosa, he became suspicious about Ms Palinkas' death."Kim had access to some dog tranquillisers," he said."Talking to the police later on they said (Judith's) death seemed to be accelerated."Mr Snibson said he immediately thought of the meals Snibson had taken to Ms Palinkas when she was bedridden."It went through my head that: 'Gee I hope she didn't drop some of those tranquillisers in her meals or something'," he said.Mr Snibson said he would have sworn Snibson and Ms Palinkas were close friends but he had seen his ex-wife manipulate people before.After her arrest, he heard numerous stories from friends about Snibson's alleged schemes to kidnap, assault and kill other people, which she denied in court.The court heard that in the decade before she was arrested, Snibson allegedly asked a friend to help her get a gun so she could obtain the deeds to a woman's house before killing her; asked one of her husband's colleagues to bash a woman badly enough to put her in hospital; and offered another of her husband's colleagues $50,000 to help her "punish" a person.Mr Snibson said he recalled one such plan from about 1996."(Snibson's friend) told me this crazy scheme Kim had to try to kidnap these people, get them to sign the house over (to Kim) and then kill them," he said."It was absolute lunacy in my mind."I don't know how she thought she would get away with it."At the time he assumed Snibson's friend had made up the story.But he believed otherwise now.