SINN Féin has said comments from a former paratrooper who claimed the actions of the British army on Bloody Sunday were a "job well done" had caused renewed hurt to victims' families.
Raymond McCartney described the remarks by an ex-soldier during a BBC documentary as "offensive and extremely hurtful".
Thirteen people died when paratroopers opened fire on civil rights marchers on January 30 1972, with another victim dying later.
The PSNI launched a murder investigation in 2012 and files were passed to the Public Prosecution Service in 2016 after police concluded charges relating to Bloody Sunday could be brought against 18 former soldiers.
The ex-paratroopers are still waiting to learn if they will face prosecution in relation to the events that day.
The soldier interviewed for the documentary, Drawing A Line Under the Troubles, was arrested by police as part of their investigation.
He told the radio programme he refused to answer any questions when interviewed by officers.
He claimed that the three people he shot at on Bloody Sunday were armed, despite the Saville Inquiry finding that all those killed or injured were innocent.
"Stick me in a jail, for what end? To what end would that help the situation in Northern Ireland?" he said.
When asked by broadcaster Peter Taylor if he stood by previous comments, made in an interview in 1992, that it was a "job well done", the soldier said: "I still believe that. They were not all innocent."
Ida McKinney, whose husband Gerry was among the victims, told the programme she forgives the soldier who killed him.
"We forgive them all for what they've done. I've no bitterness against them," she said.
However, Mr McCartney, a Sinn Féin assembly member for Foyle, criticised the former soldier's remarks.
"These comments are offensive and extremely hurtful to the families of those who died on Bloody Sunday," he said.
"They also fly in the face of the findings from the Saville Inquiry which clearly demonstrated how the victims had been murdered by the British army.
"This was not a job well done. It was a massacre of innocents."
