Murtza Chaudhry, aged 21, Arbaaz Hussain also aged 21, Zeeshan Khalid, aged 20 and Tayyab Siddique, aged 22 all died following the incident which happened at around 5.30am on 2 August.
The IOPC (Independent Office for Police Conduct) has met with the families of the four men today to review dashcam footage from the unmarked police car and to review accounts from officers.
The body says the evidence 'continues to indicate' that the grey BMW being driven by the four men was being driven 'at speed' when it passed a stationary police car on Stony Lane, Bradford.
A spokesman for the IOPC said: "We have met with the men’s families today (Thursday 9 August) to provide an update as to the progress of our investigation. This includes confirmation that we have: • reviewed the in car footage from the unmarked police car • received further detailed accounts from the officers in the unmarked police car • reviewed accounts from officers in a marked police car, which later attended the scene "The evidence continues to indicate that the grey BMW One Series car in which the four men were travelling was being driven at speed when it passed a stationary unmarked police car on Stony Lane. Following a short pursuit, the BMW hit a tree on Toller Lane."
IOPC Regional Director Miranda Biddle said: “We are continuing to support the families of the men who sadly died, and we are providing regular updates about our investigation and opportunities for them to ask further questions.
"I met with local councillors in Bradford this week to discuss our investigation and am keen to attend further community meetings in the future.
"West Yorkshire Police are fully co-operating with our investigation and we have had the accounts from the officers from the unmarked police car.“The evidence gathered by the investigation to date indicates that a marked police car passed by the unmarked police car shortly before the BMW.
"However, we understand the marked police car was not involved in the pursuit but did attend the scene after the collision, to provide assistance.
"The time between the officers in the unmarked police car noticing the BMW and them arriving at the scene of the collision was approximately one minute.
"Our investigation will establish the timings and direction of the pursuit.
"There continues to be no indication that any police vehicle came into contact with the BMW. However, all of these matters remain under investigation and I would urge anyone with any information or who witnessed these events contact us on our witness appeal line.’’