Jay Whiston murder: Police launch Facebook adverts
Police investigating the murder of 17-year-old Jay Whiston have launched two targeted Facebook adverts.
Jay, from Clacton, died in September at a party in Colchester which was organised via the social network site.
The appeals will appear on the Facebook profiles of people aged 16-22 and 35-55 who live in Colchester and Clacton.
Det Ch Insp Simon Parkes said: "We know some people who have yet to come forward and hope the Facebook adverts will help us reach out to them."
Essex Police is still searching for a knife, believed to be the murder weapon, and a red and white polo shirt, which may have been worn by the killer.
"We have taken statements from more than 140 people but are still missing key pieces of evidence that could help bring to justice whoever is responsible," Mr Parkes said.
"We're also using Facebook to reach out to parents in the Colchester and Clacton areas.
"Were your children at the party that night?"
Nine people have been arrested in connection with the case. Eight are currently on police bail until 22 March.