Ryan McGrath is still startled by the sound of helicopters.
He never used to pay attention to them but since that Friday on Bourke Street, they now mean something very different.
"I work at a hotel and I was on the rooftop a few days later and I saw a helicopter, and because of what happened on Bourke Street, I immediately thought, 'Oh no, what has happened?'"
McGrath, a restaurant manager at the Adelphi Hotel, was on Queen Street three weeks ago when Dimitrious "James" Gargasoulas, 26, allegedly mowed down two dozen pedestrians on Bourke Street and killed six others.
Three people remain in hospital, including one in a critical condition.
The floral tributes have been removed but witnesses of the attack say the horrific scenes from that day still haunt them.
McGrath saw the driver fly past, his car sending a pedestrian into the air. He went to work that night but had nightmares for a week.
"I was okay during the day then at night I'd hop into bed and I'd have these disgusting dreams, not actually Bourke Street-related but similar sort of scenarios, and that was happening every night for a week."
Karen* was at the GPO during the massacre and says the sound of police sirens and ambulances still triggers apprehension in her.
When she crosses the road, she's worried cars aren't going to stop and she has trouble sleeping. But she feels lucky to be alive.
Karen was with her daughter, 10, during the attack and says they are both still traumatised by what they saw.
"We've been reassuring her that it's not a normal situation to be exposed to and that she's safe with us. She's certainly waking up at night and coming to our bedroom and wanting to hop into bed with us."
"Unless you were there, it's really hard to comprehend the affect it did have. You don't anticipate you will be anxious, you will be distrusting, you will be crying for no reason. The sound of police sirens, the sounds of ambulances, trigger fear and chest pain and anxiousness."
More than 794 people have been referred to the Victims of Crime Victoria support agency, including witnesses and relatives of those killed, in the past three weeks.
Of that number, a massive 774 people have been linked in to a victim assistance program, while others have opted to see a counsellor of their own.
Experts predict one in five witnesses will develop a mental health condition such as post traumatic stress disorder, depression or anxiety.
Windsor woman Jess Bergin witnessed the driver allegedly stab his brother the morning before the attack and is seeking her own support.
"I haven't been contacted by Victoria Police and they haven't offered anything but my university lodge has offered me support," she said.
"I'm okay. I still have the affects of PTSD but I am seeing my psychologist."
Mr McGrath gave a statement to police but is yet to hear from anyone. He is also coming to terms, on his own, with what he saw.
The Department of Justice and Regulation said witnesses and families were being advised on how to communicate with police, organise counselling and how to prepare a victim impact statement and navigate the criminal justice system including TAC and WorkSafe Victoria.
Karen said she was impressed with the support she received from the police and Victims of Crime Victoria. Both provided her material on dealing with grief.
"There was an enormous amount of witnesses so for police to contact everybody and offer support is really quite amazing I think," she said
"We have been to Bourke Street since and placed flowers at the memorial when it was there. I guess it's part of the healing process."