A tattooed man driving an old Holden station wagon could be crucial to solving the five-year mystery of missing Melbourne school girl Siriyakorn "Bung" Siriboon.
A neighbour saw the then 13-year-old dressed in her uniform walking to school in Melbourne's outer east around 8.30am on June 2, 2011.
But Bung never made it to school.
Police on Thursday released new information regarding a possible sighting of the teenager on the day she disappeared.
A white station wagon was seen on Napoleon Road in Rowville between 8.45am and 9am and it's believed an Asian teenage girl was sitting in the front seat.
The vehicle is described as a white 1971 to 1973 Holden HQ Kingswood station wagon. It was being driven by a man in his late 30s to early 40s.
He was either bald, or fair haired, and had neck and 'sleeve' tattoos covering both arms.
"We are asking the public to think about anyone that may fit the description and had a similar vehicle or may have had access to a similar vehicle," Homicide Squad Detective Inspector Michael Hughes said in a statement on Thursday.
He said investigators couldn’t confirm if the girl in the vehicle was Bung; it was something that they needed assistance with.
“There are two specific pieces of information we are asking the public to consider, the description of the male with a large tattoo on his neck, and the description of the white coloured station wagon.
“If we can connect those two pieces of information it will improve our ability to identify the person of interest,” Insp Hughes said.
“It’s now been five years since Bung left home and failed to arrive at school that day and has not been seen or heard from since.
“We continue to hold grave concerns for her safety and are desperate to provide her family with some answers."
Victoria Police has previously released information on two other possible sightings of Bung on the morning of her disappearance - but neither have been confirmed.
Bung's stepfather Fred Pattison says the lead-up to the anniversary of the teen's disappearance has been particularly tough.
"People just don't disappear, someone knows where she is or what's going on, it's time for somebody to stand up and say something," an emotional Mr Pattison told AAP from his Boronia home.
Bung's mother, Vanidda, moved back to Thailand. She was unable to cope with constant reminders of her missing daughter while living in Melbourne.
With his wife and eldest daughter both in Thailand, Mr Pattison will take part in a police press conference on Thursday and visit Bung's former school where she would have been completing VCE this year.
In 2013, a man claimed he hit Bung with his car and dumped her body at a local reserve.
But no remains were found and police said parts of the man's story simply didn't add up.
A reward of up to $1 million for information leading to the apprehension and conviction of the person responsible for Bung’s disappearance was announced in February 2014. Despite this, the teenager has not been found.
Anyone with fresh information about the disappearance of Bung Siriboon is urged to contact Crime Stoppers on 1800 333 000.