A decision in the case of Deborah Parry and Lucille McLauchlan is expected to take at least another week.
The two women are accused of murdering the Australian nurse Yvonne Gilford, 55, in December last year.
Ms Gilford's body was found in her room at the King Fahd Military Medical Complex in Dharan with multiple stab wounds.
In a last-minute move, lawyers defending the two women yesterday presented the court in Khobar with new evidence it had requested from Australia on the mental competence of Ms Gilford's 84-year-old mother, Muriel, who suffers from Alzheimer's disease.
Under Saudi law, the victim's family have the right to accept "blood money" or compensation from Ms Parry and Ms McLauchlan in place of execution if the two are convicted.
Frank Gilford, the dead nurse's brother, has called for the death penalty on his mother's behalf as well as his own on the grounds that she is incapable of making a decision.
The victim's relatives have to be unanimous in any call for capital punishment and it is unclear whether Mrs Gilford is well enough to make a decision.
An Australian court last Friday ordered Mr Gilford to refrain from calling for the British nurses' execution until the issue of Mrs Gilford's competence was decided by the Saudi courts.
But lawyers representing Ms McLauchlan, 31, of Dundee, and Ms Parry, 38, of Alton, Hampshire, said in a statement issued in Riyadh last week that they had obtained new evidence about the mental competence of Mrs Gilford, which was due to be put to the court yesterday.
They said the new evidence was "a major breakthrough" but would not elaborate.
Jonathan Ashbee, Ms Parry's brother-in-law, said: "The judge has closed the case and has gone away to consider the verdict, which we think will take about a week."
But he said that no public announcement of the verdict would be made.
Grant Ferrie, Ms McLauchlan's fiance, is in Saudi Arabia and visited the two women in Damman central prison on Saturday and again yesterday. Their relatives have expressed concern about the women's health, which they said was deteriorating in Damman Central Prison.
However, Mr Ashbee said they were in "reasonable spirits based on what we have been telling them on what has been happening in Australia."
If the women are found innocent they will be released from prison, but if they are found guilty the case automatically goes through the appeal system.
The two nurses claim that they were forced to make confessions under the threat of sexual mistreatment from their interrogators, and they have since retracted their statements.Reuse content