The driver of a car which plunged off a pier in Donegal and killed five people may have been three times over the drink-drive limit, a post-mortem showed.
That could indicate an "element" of intoxication, pathologist Dr Catriona Dillon told an inquest in Buncrana, Co Donegal.
Sean McGrotty (49) was found to have consumed 159 milligrams of alcohol per 100 millilitres of blood, when the drink drive limit is only 50.
Evan McGrotty, aged eight, died alongside his father Sean, 12-year-old brother Mark, grandmother Ruth Daniels (59) and her 14-year-old daughter, Jodie Lee Daniels, when their SUV sank after sliding off a "slippery as ice" slipway in Buncrana in March 2016.
Dr Dillon said: "I cannot say what level of impairment the driver had, that depends on was he habitual, was he accustomed."
The inquest has also heard from rescuer Davitt Wash who said he held a boy's hand and attempted to pull him free from the sinking car.
Mr Walsh battled to extract the child from the flooding vehicle as it sank in the freezing waters of Lough Swilly but let go after he feared he would be sucked under the water.
He swam out to the Audi in a desperate bid to avert tragedy and succeeded in rescuing Mr McGrotty's daughter, four-month-old baby Rioghnach-Ann.
Mr Walsh said: "I saw a young boy inside the car trying to clamber out past the driver.
"I reached in and grabbed the wee boy, I tried to pull the wee boy out but he seemed to get stuck on something.
"When the driver sat on the window ledge I remember the car tilted and the water then started to gush into the car.
"Just as I was trying to pull the wee boy out of the car the water rushed in and I had to let go.
"The father climbed back into the car, looked back at me and said 'save my baby'."
The water gushed in and the car went under the water.
He added: "I had to let go because I was struggling as hard as I could to avoid getting sucked into the water."
Mr Walsh has been awarded a gold medal for bravery at sea.
Eyewitness Francis Crawford told the inquest emergency services arrived within 12 minutes of being called to the scene.
By the time the RNLI lifesavers arrived the Derry family's car had disappeared into Lough Swilly and the victims were floating in the water, Mr Crawford said.
There was no suggestion the speed of the response was inappropriate.
He added: "The car was floating, bobbing in the water, 10 to 15 yards from the slipway, and slowly floating, bobbing off to the right of the slipway.
"I could still hear people and the child screaming from the car, all the time the car must have been taking on water.
"I was hoping that the emergency services would arrive and the car would not go down."
He added: "I could hear sirens, the nose of the car dipped...and the car sank to the bottom."
Mr Crawford had called the coastguard for help after Sean McGrotty urged him to seek emergency assistance.
The witness said it took 12 minutes for the RNLI to arrive.
Green algae had covered the slipway and the first witness to the inquest which is being held in Buncrana added: "It was treacherous to walk on, slippery as ice."
Baby Rionaghach-Ann was the only survivor from the vehicle. Her mother, Louise James, has said the infant was her only reason to go on living.
Garda Sergeant Mark Traynor said gardai were on the scene within four or five minutes of the call but by that stage there was no sign of the car.
He said gardai were at the back gate of the station when they received the call.
He added that the RNLI responded within a similar time as its members were returning from an exercise.
Coroner Denis McCauley said: "It is a really short time."
Sgt Traynor said a life buoy was used during the incident.
Since then additional buoyancy aids have been installed and a gate prevents cars from parking on the slipway, lawyer Keith O'Grady told the inquest.
He said it appeared tyre marks on the slipway were those of the victims' vehicle.
No prosecutions were taken in the case.
Mr O'Grady said the only sign at the time was one warning people not to swim within 15 metres of the slipway.
Sgt Traynor said additional signage had since been installed.
Ms James' statement was read at the inquest.
She was about to fly home from a hen weekend in Liverpool when the incident happened.
At 6.55pm she rang her sister Jodie-Lee and she said they were in Buncrana at a play park by the shore.
A short time later Ms James said: "I got a feeling that something was not right.
"I tried to contact Sean and Jodie but their phones would not connect."
She rang her brother Nathan, asking had her mother come home, and he said she had not.
When her plane landed in Belfast her brother Joshua told her what happened.
She went directly to a hotel in Derry, saw her baby and was taken to identify the victims.
