A woman from Cambridge is being investigated by police.
It follows reports of a stabbing on Bury Road in Thetford on at 12pm on Sunday 10 March 2024.
The victim, a man in his 30s, remains in a critical condition at Addenbrooke's Hospital.
The woman, also in her 30s, was arrested and has been released under investigation.
Police are continuing to search for two men and want anyone with information to come forward.