Police are investigating whether a retired minister who died and killed four others in a road crash suffered a seizure at the wheel.
The Rev Dr Graham Mercer, 73, was driving his blue Renault Megane as it sped along a suburban Merseyside road and hit a wall before smashing into an oncoming Vauxhall Corsa.
The collision claimed the lives of six-year-old Olivia Wood, of Wrexham, her grandmother Linda Wood, 59, of Eastham Merseyside, and her great-aunt Ann Hargreaves, 71, of Bromborough, Merseyside, who was driving. All four were pronounced dead at the scene on Spital Road in Wirral, Merseyside.
Another passenger in the Corsa, Joan Roden-Jones, 64, of Wrexham, was taken from the crash scene to hospital, where she also later died.
Witnesses said Dr Mercer was driving "faster than a boy racer" and police confirmed their investigation would cover the possibility of Sunday's crash being caused by him becoming ill.
A Merseyside Police spokesman said: "The investigating officer said it is one possible avenue of inquiry they are investigating and can't rule it out."
He added it was hoped Dr Mercer's post-mortem examination would help explain if he suffered a heart attack or seizure.
Office administrator Liz Taylor, 57, whose front wall Dr Mercer drove into, recalled the moments before and after the crash. She said she thought Dr Mercer was struck with some sort of illness, possibly a seizure, causing the crash.
She said: "I was sitting in the lounge when the Megane was coming down at great speed, and the poor chappie was obviously poorly. It was a tragic accident because the chappie had taken ill.
"It wasn't a normal speed, it was faster than a boy racer and perhaps his foot was stuck on the accelerator. Emergency crews arrived very quickly but nothing could really be done. It was horrific."
