Krishna Devi Droch was hit as she crossed a junction in Handsworth in London on Thursday. She was declared dead at the scene by emergency services.
Three persons arrested on suspicion of causing death by dangerous driving have been released pending further investigation.
A fourth person, a 47-year-old man who handed himself in at a police station last night, was being questioned after being arrested on suspicion of causing death by dangerous driving.
Police believe that three cars were involved in the incident, one of which was later found burnt up.
All three vehicles sped off after the collision and the Zafira was found burned out hours later.
"We have since also recovered the Corsa and the Mondeo and all three vehicles are being forensically examined. Specially trained officers continue to support the family and the thoughts of officers remain with them at this sad time," Detective Hughes added.
The Droch family said in a statement issued through the police that "Our family has been left heartbroken. Krishna Devi Droch was not only a mother but a daughter, sister, grandmother and aunt. This is not only a loss to the family, but a loss to the community. Through her kindness and support she was the foundation of our family".