Detectives investigating the shooting dead of Baiba Saulite are in negotiations with a potential witness about his possible placement into the witness protection programme.
Senior officers are "very confident" they will secure a conviction against the man suspected of organising a contract killer to shoot Ms Saulite (28).
Gardaí have requested profiles of foreign national "persons of interest" from a number of other police forces via Europol.
Reliable Garda sources have told The Irish Times the testimony of the potential witness could be used to bring serious charges against the man believed to have ordered Ms Saulite's killing.
However, they said the witness's evidence would probably not convict the suspect for his role in the murder of the Latvian mother of two.
Instead, it would be used to mount a prosecution relating to the planned murder of the dead woman's solicitor.
"It is very early days and the DPP would have to be consulted with this because there is often a thin line between going into the programme and facing charges," said one source.
The same source cautioned that talks with the potential witness, who is a foreign national, are at a very preliminary stage.
Gardaí believe a man known to Ms Saulite ordered her murder after becoming embroiled in a very bitter dispute with her. They believe this man either paid for a contract killer or that the murder was carried out as payment for an outstanding debt.
Ms Saulite was shot dead by a suspected contract killer on the night of Sunday, November 19th, at her home in Holywell Square, Feltrim Road, Swords, Co Dublin.
Ms Saulite's solicitor, who is based in Swords, had been threatened by the man who gardaí believe ordered the young mother's murder.
Gardaí had learned from Irish criminals of a plot by foreign national criminals to source a gun with which the solicitor was to be shot. As a result of this, armed Garda patrols were stepped up around his place of work and home.
The man with whom talks are now under way about the witness protection programme was one of two foreign nationals who was asked in recent months to kill the solicitor. They were asked to do this by the man now suspected of organising Ms Saulite's killing. Both men refused.
The chief suspect then approached Irish criminals and it is thought that one of these may have carried out the murder for him. Members of Dublin and Limerick gangs are among the suspects.
The Irish Times understands there may be a case breakthrough in coming days.
Meanwhile, a senior detective involved in the investigation has said he is hopeful a €10,000 reward offered by the Crimestoppers agency may encourage key witnesses to come forward.
"This was a truly horrific crime," said Det Insp Walter O'Sullivan.
"I would appeal to all persons who enjoy life, who love life and all that life has to offer, to come forward. This is a murder, an horrific crime, a young woman gunned down in the prime of life, the mother of two children."
Irish and foreign national criminals or prisoners may have information on the killing. Gardaí have distributed leaflets in Swords in English, Latvian, Arabic and Russian asking that anybody with information come forward.
Crimestoppers can be reached on 1800 25 00 25. The Garda confidential telephone number is 1800 666 111.
