Witnesses and dashcam footage are being sought following a three lorry crash that closed the A14 for several hours.
The collision took place on the eastbound carriageway just before the A11 junction near Newmarket at 10.40am on Monday, January 17.
This caused the road to be closed, leading to extensive delays for motorists.
Fire crews worked to release a person who had become trapped in a lorry. Two drivers suffered minor injuries.
Cambridge police would like to hear from anyone who saw the collision, and are particularly interested in anyone who saw a car and a van leave the crash.
PC Doug McColm said: “We’re appealing for anyone who saw the collision to contact us and we are particularly keen to hear from anyone who saw the van and car.
"We are keen to trace them as a matter of urgency.”
Anyone with information is urged to contact Cambridgeshire police via their web chat service or online forms quoting incident 143 of 17 January.
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