GARDAÍ investigating the murder of a 50-year-old mother-of-two in Dublin's Phoenix Park believe she may have been murdered by fellow Romanians in a botched robbery.

The investigation into the murder of Eugenia Bratis in August has been described as a "slow burner" and has now shifted to probing members of the Roma community, who gardaí believe may have targeted the woman because they were aware she was earning significant sums of money begging.

Bratis was not a member of the Roma community and was living in Ireland alone, begging for money she was sending home to her ­family.

On Wednesday, two Romanian nationals were arrested on suspicion of withholding information about the murder.

The 36- and 18-year-olds were held at Finglas and Cabra garda stations before being released without charge on Thursday and Friday. A file is not yet being prepared for the DPP but detectives say the investigation is progressing well.

One problem for gardaí is that members of the Roma community that they suspect may have more information or be responsible for the killing have been difficult to locate.

The Roma community in Ireland is a transient group and gardaí believe it is possible those responsible for the killing have left the jurisdiction because of the publicity generated by the case.

"We know she had been begging and it's possible she had a falling out with other Romanians, possibly some members of the Roma community. Part of our investigation is now focusing on the Romanian community in Ireland," said a source.

"This woman was a sole operator and many other Romanians begging here work in groups.

"It's possible they didn't like how she was operating and she was targeted. It would have also been known by other people begging that she had money on her person. It is possible more than one person was responsible for her death."

Bratis had been stabbed eight times when her body was found in the Phoenix Park on 5 August. She was a mother of two grown-up children in their 20s who are still living in Romania.

She had been seen in the months before her murder begging in Dublin, mainly around O'Connell Bridge and O'Connell Street but had never before come to the attention of gardaí.

It is believed she was living in hostels and occasionally sleeping rough.

Officers investigating her murder took the unusual step of issuing a photograph of her remains to assist the investigation.