A woman accused of stabbing to death her mother's boyfriend at his Ammanford home lied to police about the condition she was in at the time, a jury has been told.

After her arrest Maxine Williams, 22, told officers she had been high on alcohol and heroin, said Elwen Evans QC, during her opening address at Swansea crown court.

"She said she had taken two bags, two wraps, of heroin," said Miss Evans. But toxicology tests revealed no trace of the drug whatsoever.

It was an example, added Miss Evans, of her willingness to tell things that were untrue, although the same tests showed she had indeed consumed alcohol.

Today, the jury is due to hear evidence from Williams' brother Wayne, now 16, who ran from the scene in Pantyffynnon Road to telephone for an ambulance from a call box.

Williams denies murdering Bernard Evans on January 22.