The jury in David Mahon's murder trial has retired to consider a verdict.

The 45-year-old has pleaded not guilty to the murder of his stepson Dean Fitzpatrick outside his apartment at Northern Cross in Dublin three years ago

Yesterday, the jurors were told they could also consider the lesser charge of manslaughter.

During four days of evidence last week, the jurors heard from gardaí, medical experts and civilian witnesses - and Ms Justice Margaret Heneghan spent almost two hours summarising what they had to say.

They heard about an incident at a gym the day before the alleged murder when Dean stole a plastic water bottle from his stepfather's bike. A duty manager said Mr Mahon was agitated and wanted him barred.

Dean's ex, and the mother of his child, Sarah O'Rourke told the jurors about an aggressive call she received from the accused in the hours leading up to Dean's death. She said he threatened to stick a knife in her head or neck if she did not get Dean to contact him.

Dave's friend Karl O'Toole was in the apartment that night. He said Dean left after agreeing to return the water bottle. He said Dave followed him and was holding a large knife when he returned less than a minute later. They left the apartment and he said Dave later told him he thought Dean was dead.

The Deputy State Pathologist said the 23-year-old died from the blood loss suffered from a single stab wound to the stomach. He said it was 14.5cm deep but could not confirm whether it was inflicted by a run on the knife or a deliberate thrust.

David Mahon, who is married to Dean's mother Audrey, told gardaí it was his fault but said it was an accident. He claimed Dean walked onto the knife and suggested he may have even wanted to.

The six men and six women have now retired to consider one of three verdicts available to them: guilty of murder, not guilty of murder but guilty of manslaughter, or not guilty.