"This is a very challenging investigation for a variety of reasons"
Detectives probing the murder of a former IRA commander shot dead in Belfast have said it will be a lengthy investigation.
Gerard "Jock" Davison was gunned down in the street close to his home in the staunchly republican Markets area on Tuesday morning. He was shot a number of times while walking along Welsh Street.
It is understood grandfather and father-of-three Mr Davison, 47, had been making his way to a community centre where he worked when he was attacked.
Police Service of Northern Ireland (PSNI) DCI Justyn Galloway said: "This is a very challenging investigation for a variety of reasons.
"We are continuing to follow a number of specific lines of enquiry and I anticipate this will be a lengthy investigation with its success depending on people coming forward and telling us what they know."
Police conducted further enquiries in the Markets exactly a week after Mr Davison was shot and appealed for anybody with information to contact them.
Detectives want to hear from anyone who left the Markets between 9.09 and 9.15am last Tuesday, from any route either on foot or in a vehicle. They also also want to hear from anyone who parked a vehicle in the Markets before walking to work somewhere else.
As the IRA officer commanding in Belfast, Mr Davison was one of the best-known republican figures in the city.
He backed Sinn Fein's peace process strategy following the 1998 Good Friday Agreement and was employed with the Markets Development Association as a community worker.
He was allegedly involved in the fight that led to the death of Belfast man Robert McCartney in January 2005 and was among three IRA members expelled following an internal investigation in the wake of the death. He was questioned by police but released without charge.
Mr McCartney's sisters, who were forced to move out of the Markets, led a long-running battle for justice for the killing of their brother following a bar argument, which took them to the White House.
The killing happened at a time when Sinn Fein was under pressure to accept the rule of law in Northern Ireland. Its decision to support the police two years later led to the formation of a ministerial executive at Stormont and the sharing of power between republicans and the DUP.
Mr Davison's uncle, Terence Davison, was later acquitted of Mr McCartney's killing.