Ann Travers says the ability of Isis to reach out to millions online is the only difference between the terror group and the IRA.
Ann's 22-year-old sister Mary was killed in an IRA ambush on her magistrate father Tom in 1984 as they made their way home from church.
"We have social media which can show everyone the true horrors of Isis and instil fear," said Ann.
"There is no difference in putting a firebomb in a hotel to setting someone on fire in a cage. When the two soldiers were dragged out of their car, beaten and shot in west Belfast, that stuck in the minds of people because it was filmed.
"Today it's in our homes on the TV, on our computers and on our phones and that makes it all the more real."
She added: "The IRA killed because it was an easy target or a good headline. They are no different to Isis."
"I often wonder if people try to forget the horrors of our past for their own mental wellbeing. They say it wasn't all that bad to try and get past it. But people are still suffering today."