Michael Fegruson was shot dead in Derry in 1993.
A 64-year-old man arrested in connection with the murder of an RUC officers in Derry's city centre in 1993 has been released.
Constable Michael Ferguson, from Omagh, was shot twice, at close range, in the back of the head by an IRA gunman in Shipquay Street on January 23, 1993.
The 21-year-old Catholic policeman was on duty at the time and was taken to Altnagevlin Hospital but died from his injuries.
One man was jailed in 2015 in connection with the murder.
The PSNI yesterday said that detectives from the PSNI's Legacy Investigation Branch had arrested a 64-year-old man in Derry on Monday.
The man has been released following questioning.
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