Claims by an IRA man turned lawyer in his book that he was involved in multiple shootings, bombings and armed robberies have been raised directly with the Prime Minister.
Theresa May was asked by the Ulster Unionist MP Tom Elliott if she would back an extradition from the Republic of solicitor Kieran Conway, a former director of intelligence for the IRA.
In his autobiography, Southside Provisional, Mr Conway said he took part in "five or six" bombings, armed robberies and fatal gun attacks against British soldiers - although he said he could not be sure his own shots caused the deaths.
During Prime Minister's Questions, Theresa May said in principle she supported bringing people to justice in such cases.
"The question of whether or not an individual would be extradited or a request would be made for extradition is for the appropriate investigation and prosecution authorities to decide," she said. "We do, of course, recognise the concerns about those cases where it is still possible to bring people to justice, and obviously we want to see that being done."
Mr Elliott said: "He (Mr Conway) stated he will never disclose information on any fellow IRA man despite knowing details of IRA actions he himself defines as constituting war crimes.
"At a time when the Secretary of State for Northern Ireland is deliberating on the correct approach to dealing with legacy issues, I asked the Prime Minister to assure me that Her Majesty's Government will apply for the extradition of this terrorist for questioning in order to grant some form of justice to the long-suffering victims and their families.
"It is individuals like Conway who indicate that we cannot expect any meaningful movement until they engage with the process and are honest about their own past. The UK Government must ensure any new agreement will not contain amnesties for the men and women of violence."
Mark Hamilton, head of the PSNI's Legacy and Justice Department, said: "We are currently examining everything that has been said by Mr Conway in order to ascertain what investigative opportunities will be progressed. Where appropriate, all actions will be considered if the evidence exists to do so."
Speaking this week, Mr Conway described how he planted a "small number of bombs".
"You would have been concerned there would be no civilians injured and then ensure your own safety in getting away, and in that order," he said.