A detective investigating the disappearance of chef Claudia Lawrence 12 years ago has said it is not too late for witnesses to come forward and end her loved ones’ “unrelenting anguish”.
Ms Lawrence, 35, was reported missing on 18 March 2009 after she failed to turn up for a 6am shift at work at the University of York.
Police believe the chef, from York, was murdered, but her body has never been found.
Ms Lawrence’s father Peter spent years campaigning for the Guardianship (Missing Persons) Bill, also known as Claudia's Law, which allows relatives to take control of their missing loved ones' financial matters.
The law came into force in 2019 but Mr Lawrence died last month without ever knowing what happened to his daughter.
Detective Superintendent Wayne Fox, senior investigating officer on the case, believes several people know, or have suspicions about, what happened to Ms Lawrence.
On the 12th anniversary of her disappearance, he is urging anyone with information to “do the right thing” and speak to him.
Mr Fox, who took charge of the investigation in October following the retirement of Detective Superintendent Dai Malyn, said: “Today, on the 12th anniversary of her disappearance, our hearts go out to Claudia's loved ones. They have endured unrelenting anguish and trauma throughout this time.
“In my view, there are likely to be several people out there who either know or have strong suspicions as to what happened to Claudia.
“For whatever reason, they have maintained a silence for 12 years. That is an awfully long time to carry such a burden of guilt. The longer you carry it, the greater the anguish you are causing to Claudia's family and friends.
“Please do the right thing, come forward and speak to me.”
Police previously said they “strongly suspect key and vital information” which would offer a breakthrough in the case of Ms Lawrence’s disappearance is being “withheld”.
North Yorkshire Police have conducted two investigations and questioned nine people in relation to her disappearance and suspected murder but no charges have ever been brought.
Mr Fox said some of the information received by the force “appears extremely interesting and sparks a whole new line of investigation”, and he urged anyone providing this information to get back in touch with as much detail as possible.
He added: “If you know something that could help us find Claudia, or those involved in her disappearance and suspected murder, please come forward. It is not too late.”
On the eve of the 12th anniversary, Martin Dales, a friend of Ms Lawrence’s father, said: "Despite the exhaustive efforts of Claudia's late father Peter, family and friends, and North Yorkshire Police, there are still no answers and it is tragic that Peter has died not knowing what has happened to her.
“More to the point, in the light of there being no-one brought to justice in the 12 years, there are still one or more people 'at large' in York or maybe somewhere else now who do know what has happened to Claudia and where she is and potentially remain a threat to the communities in which they and we live.”
Anyone with information is urged to contact North Yorkshire Police on 101.
Additional reporting by PA