Police in Northern Ireland on Thursday arrested four people in connection with last month's murder of journalist Lyra McKee.
The four, aged 15, 18, 38 and 51, were arrested in Londonderry under terrorism legislation and have been taken to Belfast for questioning by detectives.
McKee was shot while reporting on violent disturbances in Londonderry, also known as Derry, last month. The New IRA, an armed republican group, claimed responsibility for her death but also accused police of provoking the riot which preceded it.
"As part of this morning's operation detectives carried out searches at four houses in the city and arrested four people in connection with the violence which was orchestrated on the streets of Creggan [housing estate] on the evening of Lyra McKee's murder," Detective Superintendent Jason Murphy told reporters.
"They are currently in custody where they are being questioned."
The officer thanked the public for their support in hunting the journalist's killers, "including more than 140 people who have provided images, footage and other details".
The killing, which followed a large car bomb in Londonderry in January that police also blamed on the New IRA, has raised fears that small marginalised groups are exploiting a political vacuum in the province and tensions caused by Britain's decision to leave the European Union.