Police in Northern Ireland have arrested four men in connection with the murder of journalist Lyra McKee.
The four suspects, aged between 19 and 33 years old, were detained near Londonderry on Wednesday morning.
They were arrested on suspicion of terrorism and serious crimes, police said on Twitter.
McKee was fatally shot on 18 April 2019 during riots and clashes with police in the Catholic area of Creggan near the Irish border.
A republican splinter group, the New IRA, had admitted responsibility for her death, stating that the 29-year-old journalist was "standing with the enemy forces".
The group -- which opposes the 1998 Good Friday peace agreement -- had sent its "sincere and unreserved apologies" to her relatives.
Last February, police charged a 52-year-old man with McKee's murder while saying that at least more than one person was involved in the crime, and the man who had fired the shot that killed her remained at large.
In July 2020, a 27-year-old man was also arrested in connection with the investigation.
"These arrests are the culmination of a detailed two-year investigation into Lyra's murder and the events which preceded it," said Detective Superintendent Jason Murphy, head of the Northern Irish police.
"The local community has supported the police throughout the course of this protracted investigation and I wish to thank them for the continued support and patience," Murphy added.