The “shocking and senseless” killing of a journalist in Londonderry on Thursday night was carried out by “violent dissident republicans”, Northern Irish police said.
Lyra McKee, 29, was shot dead during rioting in an incident described as terrorism by detectives.
Police Service of Northern Ireland assistant chief constable Mark Hamilton said: “Our assessment at this time would be that the New IRA is the most likely to be behind this and that forms our primary line of inquiry.”
In an update on Friday, police said they believe more than one person was responsible for McKee’s death.
Deputy Chief Constable Stephen Martin said: “There was certainly more than one person involved in the murder.”
McKee – an investigative journalist who had written about the Northern Irish conflict and its legacy – was in the Creggan area amid escalating rioting where petrol bombs were thrown.
The unrest came ahead of the Easter weekend where republicans mark the anniversary of the 1916 Easter Rising, a time when dissidents are traditionally active. Images from the scene showed vehicles alight and others burnt out.
Sara Canning, McKee’s partner, told a Londonderry vigil: “Our hopes and dreams and all of her amazing potential was snuffed out by this single barbaric act.”
Politicians have widely condemned the killing. Prime Minister Theresa May said: “The death of Lyra McKee in last night’s suspected terrorist incident in Londonderry is shocking and truly senseless.”
She added: “My deepest condolences go to her family, friends and colleagues.
“She was a journalist who died doing her job with great courage.”
Irish Taoiseach Leo Vardakar said his government condemned the violence in the “strongest possible terms”.
He added: “We cannot allow those who want to propagate violence, fear and hate to drag us back to the past.”
Gerry Adams, the former Sinn Fein leader, said he hoped McKee would be “the last to die as she did”.
“Those involved are not the IRA. The IRA embraced peace. It is gone. No Republican can support the anti peace gangs masquerading as the IRA They should disband,” he wrote on Twitter.
Sinn Fein deputy leader Michelle O’Neill said the killing in Derry was a “senseless loss of life”.
She said: “I am shocked and saddened at the tragic news that a young woman has been shot dead by so-called dissidents in the Creggan estate tonight.
“The murder of this young woman is a human tragedy for her family, but it is also an attack on all the people of this community, an attack on our peace process and an attack on the Good Friday Agreement.
“I unreservedly condemn those responsible for killing this young woman.
“We will remain resolute in our opposition to the pointless actions of these people who care nothing for the people of Derry.”
Democratic Unionist Party leader Arlene Foster tweeted: “Heartbreaking news. A senseless act. A family has been torn apart.
“Those who brought guns onto our streets in the 70s, 80s & 90s were wrong. It is equally wrong in 2019.
“No one wants to go back. My thoughts are also with the brave officers who stood in defence of their community.”
Northern Irish journalist Barry McCaffrey told HuffPost UK: “Northern Ireland has always been a dangerous place for journalists, whether it’s through threats from paramilitaries, or intimidation from police, or other organisations.
“What society have we got when journalists are being killed? This isn’t the Middle East, this isn’t South America... this is Northern Ireland, this is the UK... this is April 2019 and it’s a dangerous profession.”
Lyra McKee – ‘courageous’ journalist remembered by colleagues
Belfast-born Lyra McKee, 29, was a published author with a promising career ahead of her, the National Union of Journalists (NUJ) said.
Michelle Stanistreet, NUJ general secretary, said: “A young, vibrant life has been destroyed in a senseless act of violence.
“Our thoughts are with her partner, family and many friends and colleagues. A bright light has been quenched and that plunges all of us in to darkness.”
For many people, their first introduction to her work was her piece about growing up gay in Belfast – Letter To My 14 Year-Old Self – which was subsequently turned into a powerful short film, the union said.
Angels With Blue Faces, a non-fiction book about the Troubles murder of South Belfast MP Rev Robert Bradford, was released in 2018.
Faber is due to publish her book, The Lost Boys, in 2020.
The publisher said: “Lyra was a writer of exceptional gifts and compassion, an inspiring, determined seeker of truth, and the most beloved of human beings. We are honoured to be her publisher.”
Seamus Dooley, NUJ assistant general secretary, said: “Lyra McKee was a journalist of courage, style and integrity.
“She was a woman of great commitment and passion.
“I have no doubt that it was that commitment which led to her presence on the streets of the Creggan last night, observing a riot situation in the city.”
She had worked for the Belfast Telegraph newspaper as well as a range of other publications.
Irish President Michael D Higgins said: “The people of Ireland will have heard with both shock, outrage and great sadness of the killing of the young journalist Lyra McKee in Derry last evening - a woman of talent and commitment, who was shot exercising her profession.”
Ann Travers, whose sister Mary was murdered by the IRA in 1984, said Ms McKee was a kind and gifted person.
Irish deputy premier Simon Coveney said it was a shocking and tragic death.
He said: “As we mark the 21st anniversary of the Good Friday Agreement, we are reminded that the vast majority of people of this island voted overwhelmingly for peace and reconciliation and an end to violence.
“There can be no going back to those awful days.”
Amnesty International said it was “utterly devastated” by the death of Ms McKee, who was to appear at one of its events in Belfast next month about the dangers of reporting violent conflicts.
Patrick Corrigan, Northern Ireland programme director of Amnesty International, said: “Lyra was a great young journalist, whose commitment to truth was absolute and whose laughter could light up a room.
“Lyra McKee was one of those courageous seekers after truth, with a life ahead of her and so much to give.
“Our thoughts are with Lyra’s partner, her family and many friends.”