Ms Bridie Gordon, the sister of Philomena Gillane, said yesterday the eight-year sentence imposed on her brother-in-law for soliciting the murder of his wife was "not enough".
E's News at One, Ms Gordon, who had an affair with Pat Gillane, said he deserved a long sentence as the events surrounding her sister's death had upset the lives of all the family.
"Thank God justice is done, but it won't bring back Phil," she told RTE.
She said her mother, who died outside the court in Galway after an earlier hearing, had "died heartbroken". She said she was "sorry she didn't live to see this day".
Ms Gordon, who was not present at the sentencing hearing yesterday, said she hated herself for ever having affection for Pat Gillane. "It's very hard to pull our lives together again. I'll never get over it until the day I die."