Four people have been arrested in the investigation into the murder of the journalist Lyra McKee.

The men, aged 20, 27, 29 and 52, were detained under the Terrorism Act in Derry on Tuesday morning, a Police Service of Northern Ireland spokesman said. They are being questioned by detectives at the Musgrave serious crime suite in Belfast.

McKee was shot dead while observing disorder in the Creggan area of Derry on 19 April 2019.

The New IRA claimed responsibility for the murder, which sparked headlines and revulsion across the UK and Ireland.

Simon Byrne, the PSNI chief constable, welcomed the arrests. He said in a tweet that detectives were “working hard in the pursuit of justice”.

The senior investigating officer, Det Supt Jason Murphy, renewed an appeal for information. “I have always believed that some people within the community know what happened and who was involved,” he said.

“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.

“I want the community in Creggan to think about how that horrific attack impacted them personally and how it impacted the entire community.”

The force asked for anyone with mobile phone footage to upload it to the Major Incident Public Portal at www.MIPP.police.uk.