A 57 year old woman has been arrested in connection with the murder of Lyra (pron: leera) McKee in Derry.
She's being questioned under the UK Terrorism Act by police in the North.
Lyra McKee was shot dead during riots on the Creggan estate on Thursday night.
The New IRA says it was behind the journalist's murder and has apologised.
In a statement given to the Irish News using a recognised code word, the New IRA has offered its "full and sincere apologies" to Lyra's partner, family and friends.
The dissident republican group says she was tragically killed in the course of attacking the enemy.
They say their volunteers were "deployed to engage" after police raided a number of homes on the Creggan estate on Thursday.
In the violence that followed, Lyra McKee was shot while standing beside a police van and later died.
The PSNI say that since then, over 140 people have come forward with information - and that the investigation to find her killer is continuing at a rapid pace.
Lyra's funeral takes place in Belfast tomorrow.