Garg was murdered on his way to work at Yarraville Hungry Jacks restaurant near the place of incident.
Stating that they are seeking public information in the case, Inspector Bernie Edwards, Australia's leading homicide squad detective informed that information caravan was set up near the site on Thursday, Jan 7 to enable the public to come up with any clue which will help in the investigation.
Edwards added that they are particularly looking out for a person who had taken a taxi from Somerville Road, opposite to the Hungry Jacks outlet, around 9.50 pm (local time).
"A person caught a taxi outside the news agency opposite Hungry Jack's, and we are appealing for them to come forward, or any taxi drivers who collected a fare at around the location. We believe that person is a witness and may be able to identify people who were in the park or saw the offence occur," said Edwards.
Appealing to the killer to surrender, Edward ensured the killer of his safety.
"If the person who stabbed Mr Garg is listening, we are appealing to that person to come forward. Whether he wants to ring me, my people at Homicide or Crime Stoppers, I will ensure that person's safety." Edwards said.
He condemned the killing of the 21-year-old Garg calling it an unacceptable offence.
"Irrespective of what people have been saying, and all the motives we have heard about, it is purely and simply a murder -- tragic, senseless and totally unacceptable in our society," he said.