Police are appealing for drivers with dash-cam footage to come forward following the arrest of two men on suspicion of causing death by dangerous driving in a hit and run incident with a cyclist.
The cyclist was involved in a crash with car in Stockport Road, Timperley, Greater Manchester, at about 07:55 BST.
She was taken to hospital where she died.
Witnesses said CPR was performed for up to 40 minutes, but was not successful.
The arrested men are also being questioned on suspicion of failing to stop at the scene of a road traffic collision.
The men are accused of leaving the scene, but witness reports meant that a short time later two men were arrested.
They remain in police custody for questioning.
Police Constable Phil Shaw of the Serious Collision Investigation Unit said: “Our thoughts are with the woman’s family at this difficult time.
“We have launched a full investigation into the circumstances surrounding this incident and I would ask that anybody with information contacts the Serious Collision Investigation Unit.
“We are particularly keen to speak to anyone that may have dash-cam or mobile footage of the incident.”
Anybody with information should contact the SCIU on 0161 856 4741, 101, or the independent charity Crimestoppers, anonymously, on 0800 555 111.