Officers in a marked vehicle were involved in a collision with a moped rider at the junction of Wrythe Lane and Erskine Road.
It happened just before 5pm on the 17th of June.
The moped rider, a 55-year-old man, died at the scene.
The Independent Office for Police Conduct is leading the investigation.
Witnesses should call 0300 303 5585 or emailing wrythelane@policeconduct.gov.uk
IOPC regional director Mel Palmer said: “Our thoughts are with the family and friends of the motorcyclist and all those affected by this tragic incident. Our role is to independently establish the circumstances surrounding this incident.
“IOPC investigators have already gathered a significant amount of evidence and have established that there were several people standing at a bus stop near to the scene of the incident.
“We would particularly like these people to make contact with us, as well as any other witnesses or drivers near the scene with dashcam footage.”
A post-mortem examination was held last week and the preliminary cause of death was blunt force trauma to his head and torso.
A date for an inquest to be opened has yet to be set.
