The man was shot dead in a car park outside shops on Justin Avenue at Glenroy just after 4.30am on Good Friday.
He was found lying next to a car, a red Hyundai i30, which police believe he was driving in the lead-up to his death.
Victoria Police say the shot man was known to them and had a criminal record. (James Ross/AAP PHOTOS)
Victoria Police Homicide Squad Detective Inspector Dean Thomas appealed for anyone who saw the car to come forward.
Police would not reveal the dead man's identity but Det Insp Thomas said he was known to police and had a criminal record.
"I stress at this stage it appears to be very targeted," he told reporters on Friday.
"There is absolutely nothing to link this to any of the tobacco incidents that have been occurring, or any other homicides or other shootings that have occurred.
"But we keep an open mind with everything we do."
Neighbours said they heard one shot fired in the area about 4.30am.
Police were trying to determine the man's movements before he was shot dead, and said they did not know how many people they were looking for in relation to the attack.
"We have a lot of work ahead of us," Det Insp Thomas said.
"The appeal this morning is for anyone out there that has information to share that with us."