Anthony Nguyen and Jasmine Vuong, both 17, were crossing at pedestrian lights at the intersection of Taylors and Braeswoods Roads in Delahey when they were mowed down by a car about 11.30pm on Tuesday. It is understood the teens were walking to Ms Vuong's house and had just stepped onto the road when they were hit.

Police said it appeared the driver ran a red light, as the high-school students were crossing the lights on a green pedestrian signal.

The driver did not stop, leaving the two teens for dead in the middle of the road.

The teens, from Kings Park, were found by a passer-by.

Ms Vuong's pregnant mother, Suong Phung, was visited by police about midnight.

"They said it's a hit and run and ... we have to prepare ourselves," she told reporters on Wednesday.

She said she could not understand why the driver did not stop to call to triple-0.

"Their lives were relying on that call and [the driver] ... not make any call to save their lives and he just run away," she said.

Mr Nguyen, who suffered severe head injuries, died in the intensive care unit at the Royal Melbourne Hospital on Wednesday.

Ms Vuong remains in a critical condition in the Royal Melbourne Hospital. She underwent surgery for a fractured skull on Wednesday evening. The 17-year-old is also suffering multiple broken bones, including a broken arm and a broken hip.

Police are looking for the owner of a light-coloured SUV seen in the area around the time of the crash, which has been captured on a nearby resident's CCTV footage. The vehicle may have damage to its bonnet and windscreen.

Detective Inspector Bernie Rankin has called for the driver to come forward, saying it was just a matter of time before the car was identified.

"They've been propelled a fair distance which means the vehicle was travelling at a reasonable rate of speed prior to the crash. There's no signs of skidding, no signs of evasive action," he told reporters at the scene.

Detectives are working to identify the make and model of the vehicle from debris found at the scene.

"With this type of evidence available to us, I think it's only a matter of time before we get our hands on the driver," Inspector Rankin said.

Meanwhile, road policing Assistant Commissioner Robert Hill said he could not comprehend the merciless actions of the driver.

"I cannot understand why a motorist, having struck two pedestrians, would not stop to render assistance," he said.

"It is morally just a disgrace in my mind.

"I'm very confident that our investigators will identify that person and that person will be brought to justice sooner rather than later."

Detectives from the Major Collision Investigation Unit are investigating.

Anyone who witnessed the incident or who may have further information is asked to contact Crime Stoppers on 1800 333 000.

- with Nick Toscano and Rania Spooner