Nurse Marsha Wray vanished on January 24, 1997, after dropping her children, Philippa, then nine, and Robert, then six, off at a primary school in Harrogate.
There have been no sightings of her since then and despite previous intensive investigations, searches and public appeals, police have yet to discover what happened to her.
North Yorkshire Police hopes the launch of its new Major Crime Unit, opened today at a base in Harrogate, will help “bring the person responsible for her disappearance and murder to justice”.
The new unit, which has cost £300,000 to set up, employs 31 officers and staff specialising in major crimes including homicide, kidnap and rape.
Police say the move will give fresh impetus to the investigation of long-standing cases, including that of Claudia Lawrence, the York chef who disappeared in 2009.
Det Supt Dai Malyn, head of the new unit, worked on the Marsha Wray case as a young detective and said he remained “determined now to bring closure to this case and provide answers to her family and friends”.
He added: “As with many successful prosecutions in ‘cold cases’, we rely on the support from our communities in terms of providing information we can work with and generate the necessary lines of enquiries to find the evidence and answers.
“I remain convinced that there are people who may have information that could help us with this investigation even now.”
Today’s launch marks the first time a dedicated team has been assembled in North Yorkshire, which has the lowest crime rate in the country, to investigate murder and other serious violent and sexual crimes.
Chief Constable Dave Jones said: “The new Major Crime Unit is a key development that will greatly improve and streamline the way North Yorkshire Police investigates the most serious of crimes, including murder, incidents of serious violence and sexual crimes.
“In the past when such incidents occurred, extra resources had to be abstracted from the local neighbourhood policing and CID teams to support investigations, which often run over a sustained period of time. We now have a dedicated Major Crime Unit that has the required resources to deal with serious investigations with little or no impact on day-to-day local policing.”
Anyone with information about the Marsha Wray case should contact North Yorkshire Police on 101 and select option 1, or call Crimestoppers anonymously on 0800 555 111.