Divers also searched a lake close to the former luxury home of Dr Colin Howell near Castlerock.

Specialist equipment was used, but it is understood officers are not looking for any bodies.
Howell, 50, is in custody charged with the murders 18 years ago of his wife Lesley and the policeman husband of his then lover whose bodies were found in a car filled with exhaust fumes.

At the time it was thought they pair died in a suicide pact, but detectives launched a murder investigation earlier this year after interviewing the dentist.
His former lover Hazel Stewart, who later remarried, is also charged with the double murder. Her then husband was Constable Trevor Buchanan, who at the time was an RUC scenes of crime officer.

Howell's house was put up for sale after his second wife Kyle, an American, and the couple's 10 children left Northern Ireland to begin a new life in the United States.

Howell was due back in court again today on a further remand hearing. Stewart from Coleraine is on bail.
A police spokesman said: "Searches are being carried out as part of an ongoing police investigation into serious crime.

"These searches using specialist resources are concentrated on land and a lake in the grounds of a private house at Castlerock."