The "extremely unusual case" of a retired police inspector allegedly sleepwalking during a fatal hit-and-run after a Christmas party will be determined by a judge on Friday.
Ken Grant, 72, has pleaded not guilty to several charges including dangerous driving causing death in a judge-alone trial in the Newcastle District Court.
While one expert gave evidence it was highly unlikely the father of former NSW police minister Troy Grant was sleepwalking at the time, Defence barrister Phillip Boulten SC said it could not be ruled out beyond reasonable doubt.
"Yes it is extremely unusual and he is the extremely unusual case," Mr Boulten said in closing submissions on Monday.
According to Dr Anup Desai, a specialist sleep and respiratory physician, sleepwalking occurs in about three per cent of adults.
Grant falls into 80 per cent of that category, as it began in childhood and continued throughout his adulthood.
Sleepwalking incidents include swimming in the ocean and moving irrigation pipes on a farm, with the genetic condition passed onto his son who testified he woke up in a strange woman's bed.
Grant's last documented sleepwalking incident occurred aged 59, with Mr Boulten saying his client now lived alone and it was not so far a stretch to have recurred at 70.
Grant ran into scientist Tony Greenfield when allegedly drink driving at about 11.25pm on November 30, 2019, in the Maitland suburb of Bolwarra.
He was thrown 20m forward past his wife when they were walking to their accommodation following the same party.
Grant claims he was suffering from either transient global amnesia (TGA), was sleepwalking or had sleep apnoea and was not driving voluntarily that evening.
He travelled about 850m before hitting Mr Greenfield, and another four kilometres before being pulled over by police.
He was seen driving on two blown tyres, mounting a roundabout and swerving while overtaking another car.
Bodycam footage captured a female police officer opening his car door before Grant reaches out to close it.
The Crown argues this shows an "awareness" of his actions, and rejects a claim Grant did not know police were tailgating him in particular, given they had not tried to overtake and had been following for some time.
"We say that he shows significant knowledge and understanding, he's able to talk about family connections, he's able to talk about the function ... and of his history throughout that evening," prosecutor Lee Carr said.
But when he eventually came to consciousness and said words to the effect "silly me" it related to his being drunk behind the wheel, and was not an admission that he made a deliberate decision to drive, Mr Boulten said.
When interviewed by police he says he didn't remember leaving the party, why he was on the road, nor that there had been a collision.
Another expert witness said there was strong evidence it was due to the affects of alcohol or an "alcoholic blackout".
His blood-alcohol level was first recorded at 0.108, but rose to 0.194 following toxicology tests in hospital.
"It's hard to envisage him sleeping and drinking," Mr Carr SC said, before suggesting he had a lot more than he recalled before nodding off.
Mr Boulten said his reason for driving was illogical and contrary to plans to stay, with Grant having organised a stretcher, mattress, sleeping bag and pillow.
But Mr Carr challenged this saying the usual bed he stayed in had been occupied by someone else, and there had been an issue plugging in his sleep apnoea machine.
"This is a logical reason he got in and drove," Mr Carr said.
Judge John Hatzistergos will deliver judgment on Friday.
Australian Associated Press
