Biggs said she did not see the collision but arrived at the junction where she saw people standing around a damaged bicycle, a piece of a cycle helmet and a single wireless earphone lying on the road.
Leon Dalziel-Bush, who was on his way home from work, was driving behind Mullins as he cycled on Warburton Lane as it became Paddock Lane.
He said as he approached the junction with Dunham Road on his left he noticed a black car driving so quickly that its speed “shocked” him.
“Next thing I knew it had hit the cyclist”, he said.
“At no point did the car make any attempt to slow down or stop, the car was going at such speed that by the time I processed what had happened it had gone.”
Other witnesses, including dog-walker Peter Connell, saw the black Volvo speeding past as it crossed the River Bollin into Cheshire.
“I could hear a loud dragging sound and realised it was coming from the vehicle,” he said.
“It was an unusual sound like something flapping around like a piece of cardboard or a sheet.”
The jury earlier heard how Richardson allegedly stopped on Wet Gate Lane for around 90 seconds, got out of his vehicle and attempted to pull Mullins free.
However, the jury was told, he got back into the driver’s seat and accelerated away with Mullins still beneath the wheels.
Richardson’s cousin, Gabrielle Debotte, was sitting in the passenger seat at the time, The jury has heard that she will give evidence for the prosecution about what she saw.
Mullins suffered severe internal injuries and the prosecution claim his death was caused by dragging and crushing – and not by the impact of the collision itself.
The trial continues.