Mr John Carthy attempted to contact his sister several times during the 25-hour siege at his Abbeylara home, The Irish Times has learned.
Ms Marie Carthy confirmed last night that her brother had tried to call her on her mobile phone but it was either out of range or she was on the phone. She said Mr Carthy did not leave any voice messages on the answering service.
According to Ms Carthy, two numbers were keyed into her brother's mobile phone, her number and Mr Kevin Ireland's, a friend of Mr Carthy's from Galway who he called and spoke to four hours before he died.
Mr Carthy was killed when members of the Garda Emergency Response Unit shot him four times after a stand-off with gardai at his home in April. During the siege Mr Carthy discharged 30 shots from a shotgun.
Ms Cathy said she was told by gardai that he had tried to call her once that day. "It was six weeks later before they told me he had tried to call me," she said.
According to sources close to the case, Mr Carthy tried to contact his sister more than once and it may have been up to 40 times.
She said last night her phone "definitely wasn't powered off" and that his failure to reach her was due to a steady steam of calls she was receiving that day and because network coverage was always weak around her home. "I had the phone on because I thought he might ring me," she said.
Meanwhile, the passing of the Abbeylara report into the death of Mr Carthy to an all-party Oireachtas committee has been postponed for a week.