Bloody Sunday: PSNI unit takes over investigation
A new PSNI legacy unit has taken over the Bloody Sunday investigation, and a review of letters sent to about 200 so-called republican On the Runs.
The unit was set up to replace the Historical Enquiries Team (HET).
It will also review other killings that happened before the PSNI's serious crime branch was established in 2004.
It will re-examine nearly 1,000 killings that happened during the Troubles that were not reviewed by the HET.
Sources say the task could take up to 15 years to complete.
A team of about 40 detectives and civilian staff started work on Thursday, with the number due to grow to 75 by the end of April.
The PSNI team will operate until a new Historical Investigations Unit proposed in the Stormont House Agreement takes over responsibility for legacy issues.
Paratroopers opened fire on civil rights marchers on Bloody Sunday in January 1972. Thirteen people were killed. Fourteen others were wounded, and one later died.
The 2010 Saville Report concluded that soldiers from the Parachute Regiment opened fire first, and Prime Minister David Cameron said in Westminster: "I am deeply sorry".
A fresh police investigation was opened after calls from families.
However, in November it was revealed that most of the Bloody Sunday investigation team was to be laid off in the wake of £50m cuts to the policing budget.