Four men connected to the murder of journalist Lyra McKee have been arrested in Londonderry, it has been revealed.
Detectives have arrested four men aged 20, 27, 29 and 52 under the Terrorism Act, the Police Service of Northern Ireland announced on Tuesday.
The PSNI and other authorities have called on witnesses to share information with authorities.
Following the arrests, senior investigating officer, Det Supt Jason Murphy said that he had "always believed that some people within the community know what happened and who was involved.
— Police Service NI (@PoliceServiceNI) February 11, 2020
He added: "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.
The senior official said he wanted Creggan residents to consider how the "horrific" attack had "impacted them personally and how it impacted the entire community".
"We saw widescale revulsion after Lyra was murdered and I remain determined to work with the community and local policing to convert that revulsion into tangible evidence to bring those who murdered Lyra to justice," he concluded.
— Simon Byrne (@ChiefConPSNI) February 11, 2020
The announcement comes after Ms McKee was gunned down on 18 April last year whilst observing riots near the Creggan estate in Derry as part of her research into the Troubles.
The New Irish Republican Army (IRA) claimed responsibility for the murder of Ms McKee, according to reports.
The news also comes as a breakthrough power sharing agreement on Northern Ireland in January reopened Stormont after three years of failed talks between the United Kingdom, Northern Ireland and Republic of Ireland.
The deal aims at transforming public services and building public trust in the government, following strikes from healthcare workers in December over low pay and understaffing, Northern Ireland Secretary of State Julian Smith and Irish Deputy Prime Minister Simon Coveney agreed at the time.
Days before Ms McKee was murdered, the UK government had passed strict antiterrorism legislation following a wave of terrorist attacks which took place in London and Manchester in 2017.