He was on a bread round when the killers lay in ambush, killing him at the Ennis Road station.
The victim was a brother of Owen Treacy, who was a key witness in a murder trial which resulted in life sentences for members of the notorious McCarthy-Dundon gang.
Owen Treacy and other members of the family were under armed garda protection, but his brother was not. His murder has been described by senior gardai as “a blatant attack on law and order, and the State itself ”.
Members of the McCarthy-Dundon gang are the chief suspects.
Owen Treacy himself has round-the-clock protection from the Emergency Response Unit (ERU).
Tensions are now high in Limerick following the shooting in the city this morning.
Garda units rushed to the Topaz filling station following initial reports that an armed robbery was under way.
But officers are now investigating the possibility that the victim was ‘executed’ in a carefully planned attack staged to look like a robbery.
A lone gunman is believed to have carried out the killing, shooting Mr Treacy at pointblank range.
The filling station was sealed off today as a forensic team examined the scene. The body remained at the scene during the morning.
The victim had driven his van into the fourcourt of the filling station and parked the vehicle before entering the shop.
At 6.05 a.m., the gunman struck, pumping a number of bullets into the victim, Daniel Treacy.
The breadman, who was aged in his 30s, was unable to escape his killer and died shortly after sustaining his wounds.
A source said: “He was lined up and shot in the head. It was an execution.”
The victim’s brother Owen gave evidence in court against Dessie Dundon (27) and his cousin, Anthony ‘Noddy' McCarthy (26) who are currently serving life sentences for the murder of rival crime boss Kieran Keane in 2003.
Treacy was seen as being close to the notorious Keane- Collopy gang, involved in the feud with the McCarthy-Dundons.
Dundon and his cousin lured Keane and his nephew, Owen Treacy, to a meeting at a time when the McCarthy-Dundon gang were attempting to violently seize control of Limerick’s drugs trade.
Keane was shot dead, while Treacy was left with 17 stab wounds and presumed dead by the culprits, on the outskirts of Limerick city.
Treacy survived and provided crucial evidence against Dundon.
Three other men, Christopher 'Smokey' Costelloe, James McCarthy and David 'Frog Eyes' Stanners were also convicted of the murder.
Garda sources indicated that the callous killing of the breadman going about his early morning rounds may or may not be linked to the ongoing cycle of violence being fuelled by the gangland feud which has blighted the city for a decade.
The filling station where the shooting happened is three miles from the city on the main road to Ennis.
A garda spokesman told the Herald that the scene would remain sealed off and the State Pathologist had been contacted to carry out an examination at the scene.
Senior detectives from Henry Street garda station in the city were leading the investigation.