A pensioner suffered serious injuries after a crash in Bell Street, Princes Risborough.
At around 2.10pm last Wednesday a black Ford B-Max and a bus were involved in a collision.
An 81-year-old man travelling in the Ford B-Max received serious but non-life threatening injuries .
Investigating officer PC John Belson said: “We would like anyone who may have seen this collision to come forward and to assist us with our enquiries.”
Call police on 101 or Crimestoppers anonymously on 0800 555 111.