: "She didn't even know him. They had met but they didn't know each other.
"No one deserves this but least of all her... She was beautiful. She never did a single thing wrong."
Another relative said they believed the man was stalking the house.
Celeste's mother was inside the home they shared at the time of the murder, Pina said.
She later was stopped by officers trying to run through police tape as the body was removed, and was heard screaming: "How did I not protect her?" as she was comforted by loved ones on the lawn.
Pina said the distraught mother would "never recover" and "blames herself".
She said: "She was home but there was nothing she could do."
A dark Peugeot was seen on CCTV leaving the street minutes after the murder Credit: Nine Friends and relatives of Celeste Manno comfort each other outside her home in Melbourne today Credit: Nine Friends paid tribute to 'ray of sunshine' Celeste Manno Credit: Facebook Friends and family gathered outside the blood-spattered home to mourn music lover and cheerleading fan Celeste, who was weeks from celebrating her 24th birthday.
She had a degree in criminology and sociology, and did volunteering in her free time alongside her job at a Serco call centre.
One heartbroken friend said online: "Celeste Manno was the most kind, brightest, down to earth person, who I was lucky to call a friend.
"She always knew how to light up a room with her bubbly, sweet nature.
"She was an absolute angel who didn't deserve a tragic ending like this. The world has truly lost a ray of sunshine today."
Another friend said: "Fly High Beautiful girl. The most loving, generous and kind hearted friend to everyone around her. This world can be cruel."
Serco boss Peter Welling said: "Celeste has been a warmly regarded and valued member of our team.
"Her sudden and tragic loss has deeply affected all of us at Serco and is particularly heartbreaking for our colleagues who had the privilege to work with her."
Homicide Squad detectives said they believe the victim and killer were known to each other.
Leading Senior Constable Natalie Dean said: "The exact circumstances surrounding the incident are yet to be determined and the investigation remains ongoing."
High school cheerleader Celeste Manno studied criminology at university Credit: Facebook She did volunteering alongside her job in a call centre Credit: Facebook