Police are asking motorists who may have been driving behind a 68-year-old Nancegollan man who died after a crash on April 2.
Kenneth John Yarworth was injured in the crash and died in Royal Cornwall Hospital on April 15.
A spokesman said they would particularly like to speak to the drivers of one or two vehicles who they believe may have been travelling behind the Citroen and may have witnessed the incident.
The collision took place at around 3.50pm on Wednesday, 2 April 2014 on the B3303 and involved a red Citroen car.
The vehicle, travelling towards Helston from Camborne, left the road and collided with a hedge.
Anyone with information regarding the collision is asked to contact the Police on 101, quoting log number 0501 of 020414.