Tragic details have begun to emerge about the victims of Friday night's M5 pile-up, which killed seven people and injured 51 others.
One man, Michael Barton, was reportedly killed while travelling home from a funeral with his two daughters Maggie and Emma.
Maggie Barton was also killed in the crash, according to reports, while Emma Barton was left in a coma and her partner Chris Burbell was seriously injured.
A Welsh couple who were reportedly killed in the motorway crash were named as Pamela and Anthony Adams from Newport. According to reports the couple were returning home from their daughter's home in Taunton.
Police said on Sunday that the "main line of inquiry" into the cause of the crash is a nearby fireworks display, which reportedly created a dangerous "smoke bank" on the road.
Avon and Somerset Police are now investigating the fireworks and bonfire event at Taunton Rugby Club, including how the event was organised and who gave permission for it to go ahead.
Assistant Chief Constable Anthony Bangham said the investigation will now also incorporate a criminal inquiry.
Bangham said: "What I am now able to say this afternoon is that our main line of inquiry has now moved towards the event that was on the side of the carriageway and we do believe that while there was fog and it was difficult conditions in the area, that actually from witness evidence there was very significant smoke across the carriageway that in effect caused a bank similar to a fog bank, which was very distracting and very difficult to drive through.
"We will be doing everything we can to find out as quickly as we're able to what's behind that."
"The vehicles and people who were entering into the smoke bank have just described it as being impossible to drive through and that of course causing them to brake. So we know there was brakes and then there was the impacts."
The rugby club has said previously that its display was over by 8.15pm. The motorway remained closed in both directions between junctions 24 and 25 on Sunday following the incident, which took place at about 8.25pm in wet and foggy conditions on the northbound carriageway.
The Transport Secretary Justine Greening has said the government will also investigate the causes of the pile-up, which involved 34 vehicles and in which at least seven people are known to have died.
"Some people have said that the weather was particularly bad, but I think clearly what we need to do at the moment is focus on the NHS work that's happening to take care of the people who have been injured, but also getting the motorway back open again for the public as soon as possible. I think we'll have a debate about the policy issues in the coming weeks."
The motorway remains closed between junctions 25 and 24 northbound and southbound between junctions 23 and 25. Officials said that the stretch is expected to be re-opened overnight after a final police sweep and road repairs on on Sunday or Monday morning.