Bagley died on December 7, 2018, when the car she was in with her husband, Leonard, and their two children, Eva and Flynn, was T-boned by a car driven by Dejay Rawiri Kane. He was convicted last year after driving at an estimated 124km/h and with a blood-alcohol level three times above the limit.
The crash happened at the intersection of Newcastle and Clifton Sts.
Prosecutor Mary-Jane Thomas said in her opening address the Crown's case was "a case of inference".
The Crown would need to prove manslaughter was committed by the driver and Edwards incited and encouraged him "on committing the crime by words or conduct or both".
The Crown also had to prove Edwards knew and intended to assist the driver to commit the offending.
When Edwards was interviewed by police, he allegedly said he did not think Kane had been drinking and the car was travelling about 55km/h.
"That was a lie," Thomas said.
Defence counsel Fiona Guy Kidd made a brief opening address and said the trial would not be about "what caused" the crash. The jury should focus on whether Edwards intentionally encouraged Kane to drive recklessly.
Her client did not do or have any knowledge of that, she said.
The jury heard evidence from nine witnesses yesterday.
Among them was Matthew Clifford, who saw the car speeding and followed it until the Northern Tavern Bottle Shop.
There, he saw the person he believed to be the driver of the car, go into the store to buy alcohol. He called police and took a picture of the vehicle.
Another witness, Wade Devine, said he had a "bad feeling" when he saw the green Subaru speeding that night.
The trial continues today.
