Officers are appealing for the driver of a silver Mercedes C-Class Coupe who may have witnessed a crash in which a man was killed.
The crash, which involved a Ford Focus and a Toyota Yaris, took place in Abbott Road, Mansfield, shortly after 10am on Sunday, November 8 2015.
The driver of the Mercedes was driving along Breck Lane at 10am before coming to the traffic lights at the junction of Breck Lane and Abbott Road. At this point, he was overtaken by a Vauxhall Astra and a Ford Focus before following both vehicles on Abbott Road.
The crash occurred minutes afterwards and it is thought the driver may have important information that could help with the investigation.
Anyone who witnessed the crash is urged to contact 101, quoting incident number 322 of 8 November.