Three men arrested this morning as part of the investigation into the murder of journalist Lyra McKee have been released from police custody.
The 29-year-old man was released without charge.
The 20 and 27 year-old have been released pending a report to the Public Prosecution Service.
A 52-year-old man remains in police custody.
The men were arrested in Derry this morning under the Terrorism Act and were questioned at Musgrave Serious Crime Suite in Belfast.
The New IRA claimed responsibility for murdering Ms McKee, who was shot dead in the Creggan area of Derry on 18 April 2019.
Detective Superintendent Jason Murphy has renewed his appeal for help in the investigation.
He said he has always believed that some people within the community know what happened and who was involved.
"I understand that people may be frightened to talk to us. I have previously given my personal assurance relating to anonymity for the purpose of this investigation and I renew this assurance today, as we approach the anniversary of Lyra's murder," he said.
Det Supt Murphy said he remains "determined to work with the community and local policing...to bring those who murdered Lyra to justice."
He added: "I also know that many people were recording mobile phone video clips that night and whilst we had a huge response to my initial appeal for those videos, I believe that others may exist".