An Adelaide woman who tried in vain to save a baby trapped in a car has broken her silence about the tragic night that will haunt her forever.

Ebony Baxter administered CPR to nine-month-old Kohen after his distraught father ran down the street in Elizabeth Downs begging for help on Wednesday night.

Baxter was inside her home when she heard screams.

“Does anyone know CPR? Help, help help,” the father could be heard screaming.

The father had just found his baby boy unresponsive in the family car and was running down the road with little Kohen in his arms, pleading for help.

“He went to go and kiss the little boy goodnight and that’s when he realised he wasn’t in bed,” Baxter said.

Baxter, who has infant CPR training, wasted no time responding to the emergency.

“As I was doing it, just come on, like, I just wanted to see him take a breath,” she said.

She felt a weak pulse, but it wasn’t enough to save the baby.

“You know, his face, I can’t stop seeing the way he looked,” Baxter said.

Detectives have arrested Kohen’s 31-year-old mother, Crystal Manneken, and charged her with criminal neglect.

It’s unclear how long the baby was left in the car. Police have now seized the family van as detectives try to work out exactly what happened.

“It’s hard not to get emotional about it, particularly given I’ve got a little 21-month-old, but I think it should be a wake-up call to the system,” Liberal leader Ashton Hurn said.

The tragedy will linger in the minds of everyone who tried in vain to save Cohen.

“I wish that we could have, anyone else, like anyone there, we could have done more to help him,” Baxter said.