Detectives think that clergymen and churchgoers could have clues to the whereabouts of a vulnerable teenager missing for more than a year.
Moses John and his mother Pauline Watson disappeared from their home in Northamptonshire in the summer of 2015 and are thought to be in London.
In May a judge based in the Family Division of the High Court in London made a public appeal for help.
Mr Justice Keehan said Moses was 14, had special educational needs and had been at the centre of the family court litigation.
The judge said he was gravely concerned and said it was imperative that Moses was found. Police now say it is likely that Ms Watson, who is in her 40s, has attended a church - and they want church ministers or members of congregations to come forward if they have information.
Officers say Moses is black and about 5ft 9in tall. His mother is also black and around 5ft 7in.
They say Ms Watson is from Jamaica and is thought to have links to areas of London including Croydon, Islington, Merton, Sutton, Southwark and Lambeth.
"It is likely that Moses' mother has attended church services," said Detective Sergeant Nickie Deeks, who works for Northamptonshire Police.
"It may even be that she has asked a clergyman for help or advice."
Detective Sergeant Deeks added: "We would urge all clergymen, church ministers and churchgoers - particularly in the London area - to think very carefully about whether they might have seen or had contact with Moses or his mother.
They may have been faces in a congregation, they may have been at church events, they may have needed help.
We would urge anyone who thinks that they might have any information to please get in touch.
It is vitally important that Moses is found."
Mr Justice Keehan had said in May that Moses was vulnerable.
"I am gravely concerned for his welfare," the judge had said.
It is imperative, in his welfare best interests, that his current whereabouts are made known."
He had added: "Moses has been missing for very many months. The very best endeavours of the social workers and the police, working co-operatively together, have not succeeded in finding him."
Social workers say they have concerns about the way Moses' mother has behaved towards the youngster.
They say she is thought to have mental health difficulties and has spoken of how she "hates" Moses and considers him a disappointment.