Four young friends who died when their car collided with a tree while being pursued by the police have been named.
The Independent Office for Police Conduct (IOPC) said the men who died following the crash on Toller Lane, Bradford, were Murtza Chaudhry and Arbaaz Hussain, both 21, Zeeshan Khalid, 20, and Tayyab Siddique, 22.
They were all from the Bradford area, and were described by people close to the scene of the accident as being friends.
The police watchdog, which is now investigating the incident, said that the BMW the four men were travelling in was being followed because it was moving at speed.
In a statement released on Friday, it said: "We understand at this time that the grey BMW 1 Series car in which they were travelling was pursued for a short time by an unmarked West Yorkshire Police car, due to excessive speed before the crash.
"All four men died at the scene.
"Their families have been informed and family liaison staff from the IOPC are supporting the families involved."
The police watchdog also confirmed that there was "no indication" that the police vehicle made contact with the car prior to the accident.
The IOPC also said that there was approximately one minute between the BMW being spotted by the police and it colliding with the tree at around 5.30am on Thursday, according to the evidence it has analysed.
Regional director Miranda Biddle said: "We have support in place for the families of those who have died.
"We have met with them to discuss our investigation and we will continue to update them about our work.
"My thoughts are with them, and all those affected by this incident including all emergency services involved."
She also requested that the privacy of the families involved be respected.
Mark Burns-Williamson, the Police and Crime Commissioner for West Yorkshire, said he is in liaison with both West Yorkshire Police and the IOPC to "ensure the investigation into the incident is completed as appropriately and sympathetically as possible".
Coffee shop manager Mohammed Rashid claimed to have known the men since they were boys, and claimed that they appeared to be close.
The 51-year-old said: "It's an absolute tragedy. Your heart just goes out to the families, to their parents.
"They were all polite young men, although I only knew them to greet and say hello to every now and then when they came in."