A 51 year old man has been arrested as part of the investigation into the murder of police officer Michael Ferguson in Derry in 1993.
Detectives from the PSNI's Legacy Investigation Branch detained the man the city this morning as part of their ongoing enquiries into the killing.
The man has been taken to the Serious Crime Suite at Musgrave Police Station for questioning.
A number of other men were arrested earlier this month as part of the same investigation.
Constable Ferguson was 21 when he was shot dead by the IRA on Shipquay Street in Derry.