Lisa Dorrian (25) was last seen at a party at a caravan park in the Co Down village of Ballyhalbert (Ireland) on February 28th, 2005. She has never been seen again since.
It's believed that Lisa was murdered at the party before a group disposed of her body secretly. Detectives have stated that they do not believe the murder was pre-planned, but that a handful of people at the party that night might 'hold the key' to her disappearance.
Original theories into who was responsible for Lisa's murder centered around paramilitary loyalists (UVF/LVF). However, police have since confirmed that this is not the case.
Partygoer, Mark Lovett (17 at the time), who worked as a groundsman, said that he and Lisa fled the caravan when they heard noises and saw flashing lights outside. In an anonymous account given to BBC Spotlight in 2005, the then 17-year-old explained how they lost each other in the dark at 5 am. Lovett, who has convictions for possessing an offensive weapon and drugs, said he searched for Lisa and rang her mobile, which was answered by her ex-boyfriend Stevie Thompson, who is not a police suspect.
Despite searches at the caravan park and surrounding areas (including a clay pit), Lisa's body has not been found.