The drivers or occupants of the six cars and vans are urged to contact police.
It's believed they could have information that could help detectives, as they investigate the crash which happened between junction 20, for Lutterworth, and junction 21 for Leicester shortly before 6.30pm on Wednesday 10 March.
The vehicles identified by police:
- A red Fiat Panda
 - A white Volkswagen SUV (most likely a T-Roc)
 - A black Ford Transit van
 - A dark-coloured, possibly grey, Vauxhall Corsa (2015 model)
 - A silver Renault Master van or Vauxhall Vivaro, which was travelling behind a Skoda Octavia
 - A white Mitsubishi L200
 
A man in his 30s remains at the University Hospital of Coventry and Warwickshire in a critical condition.
A 24-year-old man was also arrested on suspicion of failing to stop and has been released under investigation.
Detective Sergeant Paul Hawkins, from the Serious Collision Investigation Unit (SCIU) said: “I believe the drivers and any occupants of these vehicles may have information that can assist our ongoing investigation.
“I would therefore ask that these people contact us as soon as they’re able to. I am particularly interested to speak to any drivers who have dashcams installed in their vehicles.”
You can pass on information by visiting https://www.leics.police.uk/ro/report/rti/rti-b/report-a-road-traffic-incident/ and quoting reference 21*137236.
                                            
                                                    
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