A car seen doing laps past the home of a Melbourne woman the night she was killed could hold the key to solving the case, police say.
Teresa Paulino's sons say they want answers and to feel safe, as they appeal for information about the murder of a woman who was "loved by everyone" and "always smiling".
Daniel Paulino, 23, and Luke Paulino, 20, described their kind-hearted mother as "the best mum ever" who "did everything for everyone".
Ms Paulino, also known as Teresa Mancuso, was found dead at the back of her Reservoir home on July 15 after neighbours heard strange noises.
CCTV footage of a car, which drove down her street four times that night, could uncover who killed the 49-year-old, police say.
Her two sons, the only children of Ms Paulino, said they wanted closure.
"Whoever is out there that's done it come in, turn yourself in, and whoever knows the car they've seen, give police a call. We just want answers," Daniel Paulino said on Tuesday.
He said it had "been pretty hard" not knowing what happened and he did not know why someone would kill her.
Luke Paulino said he and his older brother had been looking after each other and sticking together.
"We're really trying to get through this for mum and make her proud," he said.
Detective Inspector John Potter said CCTV footage shows the vehicle drive south past a row of shops on Massey Avenue three times in 12 minutes on the night of her death.
The vehicle is seen a fourth time driving past the shops heading north a short time later.
Police say the footage is similar to previous information about a four-wheel drive parked in a neighbour's driveway at 9pm.
Det Insp Potter said police were looking at the possibility that it was the same car.
"We've got a number of leads, we think this could hold the key," he said.
He said it was possible that the person driving the 4WD and doing laps was watching the house.
Det Insp Potter said police need to identify the driver and that they had spoken to Ms Paulino's ex-husband Fernando Paulino on numerous occasions, who "hasn't been ruled out".
No other people have been interviewed by police in relation to the incident, he said.
A vehicle was seized earlier in the investigation that may or may not be associated with the 4WD, he said.