Lagan Valley MLA Mr Lunn was speaking following the discovery of a palm print found on a getaway van, which has been linked to a set of fingerprints. Ten men were shot dead by an IRA gang in the Co Armagh village of Kingsmills in 1976.
“I am pleased after this length of time there has been the ability to identify this crucial piece of evidence,” said Mr Lunn.
“I look forward to the investigation, as this new piece of evidence could be the key to finally achieving justice for the victims.
“The Kingsmill massacre was one of the worst atrocities in a generation full of them and the loved ones of those killed deserve closure.”