Fourth arrest in Derry mortar investigation

psniA fourth man has been arrested in Derry following Sunday night's foiled mortar attack.

Policer say detectives investigating the discovery of four mortars in a van on the Letterkenny Road have arrested a 31 year old man in the City.

The suspect has been taken to the Serious Crime Suite at Antrim police station for questioning. Three suspects arrested on Sunday night remain in custody.