Video report by ITV News Correspondent Rob Smith
Counter Terrorism Police say if the bomb used in the Liverpool Women's Hospital terror attack had detonated in different circumstances, it would have 'caused significant injury or death'.
Emad Al Swealmeen, 32, died when the taxi he was a passenger in exploded outside the hospital just before 11am on Remembrance Sunday.
Officers investigating the attack have revealed the device was made using homemade explosive and "had ball bearings attached to it which would have acted as shrapnel".
Assistant Chief Constable Russ Jackson, Head of Counter Terrorism Police North West said: "We still do not know how or why the device exploded when it did, but we are not discounting it being completely unintentional, and it is a possibility that the movement of the vehicle or its stopping caused the ignition."
Police say the terror suspect, who died in the explosion, 32-year-old Emad Al Swealmeen, had spent months gathering ingredients to make the device and used many aliases.
Police have spoken to Liverpool bomber Emad Al Swealmeen's brother, which officers said "has given us an insight into his early years and an understanding of Al Swealmeen's life and his recent state of mind, which is an important line of investigation".
He said there was no link between the incident and the Manchester Arena bombing in 2017, which he said involved a different type of device.
Taxi driver David Perry escaped from the explosion with injuries.
Mr Jackson said "significant progress" was being made in the investigation, which includes ongoing searches at addresses in Sutcliffe Street and Rutland Avenue in Liverpool.
The asylum seeker, who had converted to Christianity, reportedly arrived in the UK from the Middle East in 2014 and had an application for asylum rejected the following year, but had a fresh appeal ongoing at the time of his death.