More than one person was involved in an orchestrated bid to murder police that left one of Northern Ireland’s most promising young journalists dead, senior officers have said.
Published author Lyra McKee, 29, was an innocent bystander shot in the head by dissident republicans during serious disturbances in Londonderry on Thursday evening, they added.
Detectives from the Police Service of Northern Ireland (PSNI) blamed the anti-peace process New IRA and said the intention was to kill its officers.
“There was more than one person who was involved in this last night.”
Mobile phone footage taken by a bystander appeared to show a masked gunman crouching down on the street in the Creggan estate and firing with a handgun.
Ms McKee was standing near a police vehicle and was fatally wounded.
She was taken to hospital by officers but later died.
Prime Minister Theresa May said the killing was “shocking and senseless”.
The New IRA is an amalgam of a series of armed groups opposed to the peace process.
It claimed responsibility for a number of parcel bombs sent to London and Glasgow recently.
The threat posed to police in Northern Ireland is high.
It is understood Ms McKee had recently moved to Derry to live with “love of her life” Sara.
She was an editor for California-based news site Mediagazer, a trade publication covering the media industry.
In 2016, Forbes Magazine named her one of their 30 under 30 in media.
She had been working on a new book which had been due to be published in 2020.
Michelle Stanistreet, National Union of Journalists (NUJ) general secretary, said Ms McKee was one of the most promising journalists in Northern Ireland.
She said: “A young, vibrant life has been destroyed in a senseless act of violence.
“A bright light has been quenched and that plunges all of us into darkness.”
Causes close to her heart included helping homeless people, preventing suicide and supporting LGBT rights in the most restrictive regime in the UK.
“Have you no sense of humanity or dignity about yourself?”
Mr Martin criticised those behind earlier violent scenes during which more than 50 petrol bombs were thrown and two cars burned in the Creggan.
“Regretfully, people such as I described earlier who are completely out of step, goaded and orchestrated young people to engage in disorder,” he said.
“The police didn’t react to that disorder. We didn’t respond with any use of force, we absorbed it.
“We were there to do search activity. We did not want in any way to make the situation worse.”
He defended the decision to launch an operation earlier on Thursday aimed at thwarting dissident plans for “imminent” violence.
Anti-peace process sentiment in Northern Ireland’s second city has been demonstrated in recent attempts to bomb the courthouse and the calling off of a community youth event after police were invited.
Mr Martin condemned those whose sole purpose in life was to try to attack his officers and destroy the peace.
“Today is Good Friday and it’s a cruel twist in our history that 21 years ago the majority of people in Northern Ireland signed up to the Belfast/Good Friday Agreement yet here we are today mourning the loss of a talented young woman, a young journalist who was also a daughter, a sister and a partner.
“This is a dark day.”
Assistant chief constable Mark Hamilton said it was a calculated and callous act to bring a firearm into a residential area.
“Bullets stop somewhere, and on this occasion they stopped fatally.”
A vigil was held in the Creggan in Ms McKee’s memory, organised by local residents who said they felt sad and angry.
Spokesman George McGowan said: “This behaviour is not in our name – we have all been wounded by these actions.”
A book of condolence was opened at the city’s Guildhall.
Northern Ireland Secretary Karen Bradley, speaker of the US House of Representatives Nancy Pelosi, DUP leader Arlene Foster and Sinn Fein deputy leader Michelle O’Neill were among those to pay tribute.