Police detectives have announced they will re-interview witnesses who gave evidence to the Saville Inquiry into Bloody Sunday.
The news came on the anniversary of the killings as hundreds of people gathered for a minute's silence at the Bogside memorial in Londonderry.
Detective Chief Inspector Ian Harrison said: "For the investigation to be as comprehensive and effective as possible, police are asking for public support in the form of witnesses who gave evidence to the Saville Inquiry to now make statements to detectives.
"Contact has also been made with former military witnesses.
"During the Saville Inquiry it was ruled that anonymity was granted to any former soldier who gave evidence unless his name was clearly already in the public domain.
"That ruling does not automatically carry over to the current police investigation.
"Anonymity will be a matter for a future court to consider."
The majority of the families want to see the soldiers who were responsible for Bloody Sunday face prosecution.
John Kelly, whose brother Michael was the youngest to die, is among those who want charges brought.
He told the Belfast Telegraph the failure by police to arrest any soldier so far had infuriated the families.
"In our discussions with police we were extremely angry to discover that not one single soldier had been arrested to date," he said.
Kate Nash, whose brother William was killed, said: "I have been bewildered and frustrated as to why no soldier has yet been questioned by the police.
"This for me and a lot of the families is the biggest stumbling block.
"We were told previously that the police know the identity of the nine shooters, so I am at a loss as to why they have not been questioned yet."
East Londonderry DUP MP Gregory Campbell said the investigation could "prove disastrous in how our society deals with the past".
He said: "There has already been a £200m politically-motivated Inquiry to ask these same questions to the same people.
"Forty-three years after the event, does anyone believe new information or evidence will emerge leading to prosecutions?
"This is a further futile waste of resources which will cause division once more.
"The need to move on must be greater than the desire to rewrite the history of the past."
Veteran journalist Eamonn McCann, who yesterday launched his latest publication on Bloody Sunday, remained sceptical about the enthusiasm of police to pursue the soldiers.
He said: "It is extremely strange that the police are looking for witnesses before they have spoken to the soldiers, even though they know the names and addresses of those soldiers.
"It concerns me, too, that the spotlight is on the rank-and-file paratrooper, but the officers that sent them into the Bogside are getting off scot-free."
STORY SO FAR
A team of officers from England and Scotland has been assembled to investigate the nine soldiers who killed 14 people on January 30, 1972 with a budget of £4m over the next four years. More than 1,000 witnesses and former soldiers are being asked to make statements as part of the criminal investigation. Police insist it is necessary to re-interview witnesses as officers are precluded from using Saville testimony in a criminal inquiry.