South Australian police divers have launched a new search for the body of 15-year-old Adelaide girl Melissa Trussell, who went missing in 2000 in a suspected double murder.
Melissa and her 33-year-old mother, Rosemary Brown, were last seen in Blair Athol, in Adelaide's north, at about 2:30am on Saturday, May 13, 2000.
Ms Brown's body was found seven weeks later in mangroves at Garden Island in Adelaide's north-west on July 2, but Melissa's body has never been found.
A previously unsearched area of water and mangroves on the northern side of Garden Island was the focus of the fresh search on Friday.
SA Police suspended the search on Friday afternoon, and said a vehicle had been located in the area.
They said a section of the car's front grill was removed and will be used to help identify the vehicle, with further inquiries to be undertaken to determine whether it is connected to the murder of Ms Brown and suspected murder of Melissa.
The search will recommence on another day, with SA Police flagging they may recover the entire vehicle for examination.
Earlier on Friday, Detective Superintendent Darren Fielke said the "extensive and thorough" search may take several days.
"The reason we are here today is purely as a result of the work that the major crime detectives have done in the cold case team to identify areas that haven't been searched prior to today," he said.
"We are hopeful that we will find Melissa's remains today, but we are not sure that we will, but we are hopeful that we will."
Asked why the area was not searched before, Superintendent Fielke said he did not know.
"It is just one of those areas that we have identified during our cold case review that just wasn’t done," he said.
"So I can’t speak to why it wasn’t done 25 years ago.”
Police believe the teenager and her mother were murdered but detectives have no motive and no one has ever been charged for any offence relating to their disappearance.
According to SA Police, a number of people have been identified as persons of interests over the past 25 years.
"Twenty-five years is a long time, a lot of water goes under the bridge, people's allegiances change overtime, people forget about it, some people don't forget about it," Superintendent Fielke said.
"We are always in there prodding and poking away, trying to get a breakthrough.
"So, in some ways, the passage of time is helpful to us because of those allegiances that break down, it might just be time for someone to come forward and tell us what really happened."
Search comes after public appeal
Earlier this month, Melissa's father, Barry Trussell, and her sister, Kayla Trussell, joined renewed calls from police for information on the case.
The appeal marked 25 years since Rosemary's body was discovered.
Since that appeal, police have received a number of calls, which investigators have since been working through.
Detective Superintendent Darren Fielke said the information has been useful.
"We are always looking for information no matter how minute that information might be, how insignificant someone might think that information might be," he said.
"It might just be the piece to the puzzle we are looking for, in terms of trying to solve this long-term investigation."
SA Police also released a new image this year of Melissa in an attempt to spark public interest in the cold case.
According to Crime Stoppers SA, Rosemary was evicted from the Windsor Gardens Caravan Park on May 3, and moved around in the days before her disappearance.
A reward of up to $1,000,000 has been on offer for information and assistance that leads to the conviction of those responsible for the suspected murder of Melissa, while a reward of up to $200,000 has been on offer for the same in Rosemary's case.
Those with information are asked to contact Crime Stoppers on 1800 333 000 or online.
