Catholic breadman Dermot Hackett was shot dead by Stone at the wheel of while on his rounds in 1987. At the time it was claimed he had republican paramilitary links, but this has always been strenuously denied by his family.
Last year Stone met with Mr. Hackett's widow, Sylvia for the controversial BBC series 'Facing the Truth'.
Following Friday's security breach, Mrs. Hackett, who lives in Strabane, said Stone had now "shown his true colours".
"He said he had finished with guns and violence but look at him now.
"When he met us he came in with a walking stick. I didn't see any walking stick up at Stormont."
Mr. Hackett's brother Rodney added that he believed the 51-years-old had "become unhinged".
"I would say the whole thing has just got on top of him now. This is a really stupid action, what was he going to gain from it?
"He's a spent force now but when he came out of prison he had a high profile. Maybe this is his natural reaction to losing his profile and he wanted into the limelight again."