Police are to open a murder inquiry into the Bloody Sunday killings 40 years ago in Northern Ireland.
The probe has not started because the resources are not available for the four-year investigation, senior officers said.
It follows the Saville Inquiry's report which said civil rights demonstrators shot dead by British soldiers in Londonderry at the height of the Troubles were innocent.
Chief constable Matt Baggott said: "It is a matter that I think we should be investigating and will be investigating."
The Police Service of Northern Ireland has consulted prosecution lawyers as it prepares to open a major investigation. That would require a team of 30 and extra specialist help which are not available at present.
Assistant chief constable Drew Harris said: "This will be and is a long and resource-intensive investigation. Sustain it we will, but there are some questions we need to bring to the (Policing) Board in relation to prioritisation of that and other issues in regard to legacy matters."
Thirteen people were shot dead when soldiers opened fire on civil rights marchers in Londonderry on January 30, 1972. Another man died five months later.
A report by Lord Saville unequivocally blamed the Army for one of the most controversial days in Northern Ireland's history.
Key findings included: No warning had been given to any civilians before the soldiers opened fire; none of the soldiers fired in response to attacks by petrol bombers or stone throwers; some of those killed or injured were clearly fleeing or going to help those injured or dying; andn one of the casualties was posing a threat or doing anything that would justify their shooting;
It also found many of the soldiers lied about their actions; and Northern Ireland's Deputy First Minister Martin McGuinness of Sinn Fein was present at the time of the violence and "probably armed with a sub-machine gun" but did not engage in "any activity that provided any of the soldiers with any justification for opening fire".