Mystery posters urge 'breaking of silence' over murdered teen Jonathan Cairns
Police are investigating the appearance of posters calling for information about the murder of a teenager 16 years ago.
Jonathan Cairns was 18 when he was killed after a night out in April 1999.
Officers are now probing the circulation of hundreds of flyers in Ballykelly appealing for information over the murder.
The posters, which have the headline 'Break your silence' have not been circulated by his family, the police or the Justice for Jonathan Cairns Facebook page.
A police spokesman said officers were conducting enquiries in the area.
The body of the Co Londonderry teenager was discovered in a shallow grave in Loughermore Forest, five miles from his home in Ballykelly.
His mother and father, Hazel and Raymond, last saw him outside a chip shop in the village at around 1.30am as they drove home from a function.
They waved at him and thought about giving him a lift, but let him be as they thought he would soon be home. They would never see him again.
When the apprentice electrician failed to come home in the early hours a search swung into action and his bloodstained clothes were discovered folded neatly in a pile not far from Jonathan's home.
His wallet and driving licence were also nearby.
The search continued until Jonathan's cousins spotted drag marks in Loughermore Forest. After following them, they discovered their relative's body in a shallow grave.
While one man was jailed for perverting the course of justice, no one has been convicted of Jonathan's murder.
Detectives reopened the case in 2013, saying they were following new lines of enquiry following a review of the investigation.
There is a £30,000 reward for any information leading to a murder conviction.