The attorney general should investigate whether British defence secretary Gavin Williamson has interfered in the judicial process, according to the Bloody Sunday families.
Speaking recently in a BBC interview, Gavin Williamson said he was saddened that protection against "spurious prosecutions" would not be given to service personnel in time for proceedings announced on Thursday in Derry.
John Kelly, whose 17-year-old brother Michael was killed, said the attorney general should decide if the defence secretary or other politicians have broken the law.
Mr Kelly said: "If they have, they should be charged.
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"They cannot attempt to interfere in a judicial process just because they don't like it, or because their voters don't like it."
MPs have campaigned for a statute of limitations which would prevent troops from being prosecuted for serving their country, including in Northern Ireland.
Mr Williamson told Political Thinking With Nick Robinson's BBC Radio 4 podcast: "We need to give protections to service personnel ... to ensure we don't have spurious prosecutions.
"No-one in the armed forces wants to be above the law, but what we did need to do is ensure that they do have the protection so that they don't feel under threat.
"It's not just about Northern Ireland, but about Iraq and Afghanistan, conflicts before that and in the future."
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In response to a question about whether that would make a difference to Bloody Sunday, he continued: "Sadly, I don't think that will come in time.
"I think we have to ask a real question as to Northern Ireland has moved on. There's been so much progress - we've got to look to the future, not at the past."
Soldier F is to be prosecuted for murder, the Public Prosecution Service (PPS) said this morning.
Afterwards, Mr Williamson confirmed the Ministry of Defence would support Soldier F and pay all legal costs.
He said: "We are indebted to those soldiers who served with courage and distinction to bring peace to Northern Ireland.
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"The welfare of our former service personnel is of the utmost importance and we will offer full legal and pastoral support to the individual affected by today's decision. This includes funding all his legal costs and providing welfare support.
"The Ministry of Defence is working across government to drive through a new package of safeguards to ensure our armed forces are not unfairly treated.
"And the government will urgently reform the system for dealing with legacy issues. Our serving and former personnel cannot live in constant fear of prosecution."
Alliance Party leader Naomi Long Mr Williamson after he called for former service personnel to get greater protection from prosecution.
Mrs Long tweeted: "Today is not the time for this debate, but rather for sympathy with the families and for respect for due process and the rule of law. As a Minister in HMG Gavin Williamson should know better than to in any way seek to challenge, directly or indirectly, the PPS decision."