Linda Mulhall (31), the mother of four young children, was convicted of the manslaughter of Kenyan man Farah Swaleh Noor (38) after the 13-day trial.

Her younger sister, Charlotte (23), was found guilty of murdering the 38-year-old. His dismembered remains were found floating in black plastic bags near Ballybough. His head and penis have never been found.

The girls' mother, Kathleen Mulhall, who left her husband John for Noor, did not attend the trial and is awaiting a decision from the DPP as to whether she will face charges. She is believed to be living in London.

John Mulhall, from Kilclare Gardens, Tallaght, who was not implicated in the crime, killed himself as his daughters awaited their murder trial. Linda Mulhall became a heroin and alcohol addict and the case had to be adjourned earlier this month.

The jury found her guilty of manslaughter by a 10-2 majority while her sister Charlotte was convicted of murder by an 11-1 majority. The verdicts were announced shortly after 2.30pm yesterday.

The murder trial heard that Noor was in a relationship with the sisters' mother Kathleen Mulhall, and that on the night of 20 March 2005, he met his death in a knife and hammer attack after making advances on Linda.

Earlier that day, both sisters had taken ecstasy with their mother on the Liffey boardwalk and Kathleen Mulhall had later spiked Noor's drink with ecstasy. In statements to the gardai, both sisters admitted to cutting up his body afterwards and bringing it in bags to the canal where it was dumped. The court heard that the man's head was brought in a child's schoolbag to a park in Tallaght, but it has never been recovered.

After yesterday's verdicts, detective inspector Christy Mangan told the court that Linda Mulhall had one minor previous conviction and Charlotte had a number of minor convictions. Both had histories of drug and alcohol abuse, he said. Linda had suffered from violence at the hands of a former partner who had received a jail sentence for cruelty to her children.

Both sisters, the garda said, came from "troubled, tough" backgrounds. Judge Carney remanded both in custody for sentencing until 4 December.

He said he would await the possible submission of a victim impact statement before applying the mandatory life sentence on Charlotte Mulhall. Both sisters hugged and kissed their brother before being led away by gardai.