Vic son can't forgive mum's killer

A Melbourne man whose mother was struck and killed by a speeding stolen car will never forgive the hit-and-run driver who left his mum for dead in the gutter.

Jennifer Moller, 54, was leaving bingo when she was mowed down as she crossed a road to join her waiting husband in Frankston in 2012.

Ms Moller died on the roadside 30 minutes after the crash despite the best efforts of paramedics and a passing nursing student.

"She was my dad's rock and my rock and I just can't forgive him," Jennifer's 20-year-old son, PJ Moller, told reporters on Monday.

"We're still trying to recover.

"Hearing about (her death) and seeing her in the coffin, it took its toll on me and we're trying to get through this but it's really hard."

Had Jennifer been able to cross the road safely, she'd have ended up in the arms of husband John, who had come to pick her up and take her home.

Instead, John is haunted by the memory of his wife's death.

"She took one step towards me and the next minute she was in the gutter," he told reporters.

"In my mind, I can still see where she's laying - that's never going to change."

Information from witnesses at the time was good enough for police to find the Mercedes sedan involved and arrest a 34-year-old man.

But investigators still lack the evidence that ties the offending driver to the crime.

"Unfortunately, we had insufficient evidence to prosecute any person," Detective Sergeant Daryll Out said.

On Monday investigators announced a $250,000 reward for information leading to a conviction, in the hope the driver's associates start revealing the truth to police.

Crime Stoppers urged people to come forward, noting they don't have caller ID or any form of IP tracing.

"We don't care who you are, just what you know," Crime Stoppers Victoria General Manager Cathy Rhodes said.

"Even if you think it is insignificant, the information you hold could be the final piece of the jigsaw."