There were scenes of grief at the hospital last night as family and friends of the dead man -- whose younger brother Paul was murdered in 2004 -- attempted to come to terms with the second gun death of a loved one.
Gardai are probing whether the wounds in the second incident may have been self-inflicted.
Christopher Warren's younger brother Paul (24) became one of the first victims of the Crumlin/ Drimnagh feud when he was shot dead in a south inner city pub in February 2004 -- a drugs war that went on to claim 15 lives.
Senior sources say that last night's gun death is "very unlikely" to be linked to the feud but "gardai are keeping an open mind".
Gardai are working on the theory that Christopher Warren from St Theresa's Garden's, Dolphins Barn, was shot in the Arbour Hill area of Dublin's north inner city and was driven to St James's Hospital by one of his associates.
A scene across from a petrol station in the Broadstone area close to King's Inn was sealed off by officers last night as a forensic analysis took place.
A source explained: "Mr Warren and a number of his associates had spent yesterday drinking and gambling in the Meath Street area but for some reason they went across the river to the Arbour Hill area in the early evening.
"When they reached the northside, they became separated and went off in different directions.
"It seems that some time after 6pm, Mr Warren alerted one of his associates that he had been shot.
This individual has said that he found Mr Warren on the ground -- he then brought him to St James's Hospital and left him there."
The car the two men had been travelling in was found at nearby Cork Street and the vehicle is today being foren-sically examined by specialist gardai.
Sources say that gardai are keeping an "open mind" on all aspects of the investigation and are not ruling out that Warren was the victim of "accidental gun discharge".
"Gardai cannot rule out that this was some kind of terrible accident," a source said.
"Christopher Warren cannot be described as a gangland criminal -- however he was a prolific burglar and had been for two decades," the source added.
The victim was extremely well known to gardai and was one of the main targets of Operation Acer -- the huge drive against burglaries in the capital.
Warren had dozens of convictions dating from the mid-1990s, including one from 1998 in which he was convicted of two handbag snatches within 15 minutes in the Castleknock area.