A second person has been arrested in a day by police investigating the disappearance and murder of Lisa Dorrian.
The 25-year-old from Bangor, Co Down, was last seen alive on 27 February 2005 after attending a party at Ballyhalbert Caravan Park.
Despite extensive searches in multiple locations and campaigning by her family, Ms Dorrian's body has never been found.
Police said a 42-year-old man was arrested in Scotland on Wednesday on suspicion of murder, assisting offenders, withholding information and preventing a lawful and decent burial.
Hours earlier a 40-year-old woman was arrested in Bangor.
She was arrested on suspicion of murder, assisting offenders, withholding information and preventing a lawful and decent burial, and remained in police custody on Wednesday evening.
Detective Chief Inspector Kerrie Foreman acknowledged the support of Police Scotland, as well as the PSNI's Cross-Border Transit Officers.
"It's almost 21 years since Lisa's disappearance and murder. That's 21 years of torture for a loving family," she said.
"I am keen to take every opportunity to encourage anyone with information to do the right thing and come forward."
