Police are searching a caravan park where a missing Co Down shop assistant was last seen alive in 2005.
Lisa Dorrian disappeared after a party at the site in Ballyhalbert, Co Down, and detectives have said they believe the 25-year-old was murdered.
Detective Superintendent Jason Murphy, who is leading the investigation, said: “The determination of the Police Service of Northern Ireland (PSNI) to bring those who killed Lisa Dorrian to justice is as strong today as it has ever been.
“I can confirm that a large-scale search operation is taking place today in the caravan park in Ballyhalbert where Lisa was last seen alive, as well as the disused airfield behind.
“We will also be searching a number of other areas over the coming days.”
Police have pursued thousands of lines of inquiry in relation to the murder.