Ann Travers appeared before a committee on Wednesday in support of proposed legislation that would block convicted killers from becoming special advisers at Stormont.

Her sister Mary was fatally shot as she left mass with her father, a judge, in Belfast in 1984.

Mary McArdle was sentenced to life behind bars that year for her part in the murder of the 22-year-old, but was released early under the Good Friday Agreement.

In May last year Ms McArdle was appointed to the post of special advisor to the Sinn Féin Culture Minister Carál Ní Chuilín.

In those few seconds my stomach heaved and I felt like I was going to be sick. My head whirled and I remember panicking and saying no, no, no. It was like I was being told Mary was dead again.

Ann Travers

On Wednesday, Ms Travers appeared before the Assembly's Finance and Personnel Committee.

The mother of five is undergoing treatment for cancer and wore headscarf as she addressed MLAs.

She told members that hearing of Ms McArdle's appointment to the £60,000 a year role was like being punched in the stomach, and caused her to suffer flashbacks to the murder.

"It was just something out of this world, I cannot emphasise how much that affected me," she said, during an emotional appearance in which she also appealed for Ms McArdle or her Sinn Féin colleagues to reveal who else was involved in her sister's murder.

"I found myself frozen reliving running down Winsor Avenue to my Mum leaning over my Dad saying my poor husband, my poor husband, somebody please help my poor husband.

"Dad mumbling and trying to take off his watch and Mary lying on the gravel."

She clashed with Sinn Fein's Mitchel McLaughlin over what she said was his attempts to justify IRA murders.

Mr McLaughlin replied: "If you only ask one side of the conflict to account for themselves then in effect you paralyse them because they are looking across the table and saying 'well who were we fighting, who was shooting at us, who threw the first stone or who drew the first baton'. There is history.

"Your mother and father went through a terrible experience and you've spoken eloquently about it. Your sister lost her life in that. But they were born, as we all were, into a society that was already divided and there is a long history here and we are trying to deal not with what Mary McArdle did as an individual, we are trying to deal with why weren't these issues addressed in the past."

The DUP's Paul Girvan said: "I think you have brought the focus back on to the victim which I feel is where the focus should be, not upon the perpetrators who seem to be the people who have been rewarded up to now as opposed to the victim."

Ann Travers came to Commitee to support the Special Advisers Bill which would prevent anyone who had served five years in prison from holding the £60,000 per year post.

"I do feel this Bill would be a signal for all victims, even for victims who are looking for answers elsewhere, it would be a very strong sign that actually victims are being supported," she said.

"There is a lot of conversation about how we deal with our past and how we deal with victims - well, one of my things would be: listen to victims, consider them and respect them."

The bill is likely to go before the Assembly by Spring next year.