A Today Show reporter unknowingly witnessed the same maroon vehicle that ran down pedestrians in Melbourne, hours before the attack.
Neary Ty was standing on the footpath in Windsor, 5km southeast of Melbourne, about 8am on Friday when a car approached and the driver started "ranting and raving and swearing".
The journalist was covering a stabbing in the area that police now say was carried out by the same person who drove his Holden Commodore through crowds of people in the Melbourne CBD shortly before 2pm.
Police confirmed three people were dead, including a child, and at least 15 more were injured when the driver, a 26-year-old man, "deliberately" targeted pedestrians at Bourke Street Mall.
Hours earlier, the same man is believed to have shouted at the Channel 9 reporter in the street.
"We were doing a live cross this morning for the Today Show around 8am this morning about this stabbing in Windsor when the Holden Commodore pulled up behind me," Ty told Nine News.
"The man started ranting and raving and swearing. He was waving his red hat out of the window. At this point I was live on air. I couldn't see what was going on.
"My cameraman told me he put his finger towards this man to be quiet because we were on air.
"That's when the man fled the scene fish tailing in the rain and nearly taking out a number of cars."
The reporter said the driver returned the scene 10 minutes later as the crew was packing up.
"He was parked on the side of the road. We thought it was a bit strange he was there. We had no idea who he was.
"I walked past him and I noticed that he was wearing a gold chunky bracelet which was similar to a gold chunky necklace that was found at the scene during this fight.
"He was there for a while. He didn't seem erratic while he was sitting in the seat. He remarkably was there around 10 minutes after police and SES had left the scene. We packed up and left."
She said when news broke of the carnage in Melbourne's CBD, her cameraman called her to say: "I think it's the same car that's involved."
"We look at the horrifying amateur vision of that driver driving erratically and noticed there was a bit of green tape underneath the registration plate. That's when we realised it was the same man."
She said it was "certainly very shocking, very sad to hear this man's been involved in this awful tragedy in Bourke St".