West Midlands Police launched an investigation after a Skodia Fabia crashed into a tree in Bromley Lane, on Tuesday, October 13.
Joshua Parkes, Lucy Tibbetts and Isabelle Floyd died at the scene, while Nathan Cartwright died on Saturday from his injuries.
Another teenage girl, aged 16, who has not been identified by police, remains in hospital in a critical but stable condition.
The Independent Office for Police Conduct (IOPC) are investigating the circumstances prior to the crash.
A West Midlands Police spokesman said: "Our Serious Collision Investigation team are continuing to investigate the circumstances around the deaths of four young people in Kingswinford last Tuesday [October 13]."
"Initial investigations have established that the police vehicle was not in the immediate vicinity of the Skoda Fabia at the point of collision.
"The Independent Office for Police Conduct (IOPC) have now commenced an investigation into the circumstances prior to the collision.
"The police vehicle was transported from the scene to ensure that all relevant diagnostic evidence could be recovered to assist the investigation, as is normal procedure.
"Our thoughts remain with the families and friends of all involved."
Meanwhile, Crestwood School and 6th Form, where Lucy and Nathan were former students, will be starting fundraising in memory of them this week.
A statement from headteacher Caroline Sutton said: "Following the tragic loss of two of our former students, Lucy Tibbetts and Nathan Cartwright, in the accident on Bromley Lane last week, we will be starting our fundraising for them this week.
"This Friday I would like everyone to 'Shine Bright for Lucy and Nathan'. Please wear your brightest clothes and let’s fill the school with colour.
"There will be buckets around school from tomorrow for students and staff to make donations and if any parents or friends of the school would like to contribute please drop your donations in to reception.
"With the money raised, I will be meeting with Lucy and Nathan’s friends in school and after consultation with their families decide on the best way of honouring these two wonderful young people who will always be part of the Crestwood Family."
Fundraising pages have also been set up for each of the victims, with a combined total of more than £12,000 raised by Tuesday morning.
A further fundraising page has been set up for the 16-year-old girl in hospital and has so far raised more than £2,500.
Dozens of photos, flowers, cards and other tributes have since been left at the scene of the crash and hundreds of balloons were released in memory of the victims at Dell Stadium in Brierley Hill on Saturday.
Meanwhile the police investigation into the crash is continuing and anyone with information is asked to get in touch by calling 101 and quoting log 4469 of October 13.
To donate to Nathan's fundraiser go to gofundme.com/f/nathan-cartwright, to donate to Joshua's fundraiser go to gofundme.com/f/help-raise-money-to-help-the-family-of-josh-parkes, to donate to Lucy's fundraiser go to gofundme.com/f/rip-lucy-tibbetts and to donate to Isabelle's fundraiser go to gofundme.com/f/izzie-floyds-fundraiser.
We are not sharing the link to the fifth page to avoid publicising the victims' name.