A 29-year-old journalist covering a night of unrest in Northern Ireland was killed by a militant group earlier this month, helping stoke fears of additional violence as the United Kingdom works out a deal to leave the European Union.

Lyra McKee was covering rioting in Londonderry, which broke out after police raided a housing complex to search for explosives and weapons they believed were going to be used by militant dissidents, when she was shot. Days later, police announced they believed the New IRA, a militant republican group, was responsible for the attack.

The New IRA later admitted responsibility, releasing a statement five days after McKee’s killing saying she was not the intended target.

“In the course of attacking the enemy Lyra McKee was tragically killed while standing beside enemy forces,” said the statement, which was given to newspaper The Irish News. “The IRA offer our full and sincere apologies to the partner, family and friends of Lyra McKee for her death.”

Some fear that the 1998 Good Friday agreement, which ended decades of sectarian violence between republicans and unionist paramilitary groups, may not survive if the U.K. leaves the European Union without a deal.

Earlier this year, a Londonderry car bomb attack and several explosive devices sent by mail were attributed to the New IRA.

The historic peace agreement between the British and Irish governments, as well as most of the political parties in Northern Ireland, described how Northern Ireland would be governed by a power-sharing agreement and ended 30 years of violence — a period known as “the Troubles” — that left more than 3,600 people dead.

Currently there are over 140 areas of cooperation between Northern Ireland and the Republic of Ireland, according to the Council on Foreign Relations. This includes everything from health care services to energy infrastructure and policing.

There have been no customs and immigration checks along the border since the Good Friday agreement, and there is freedom of movement thanks to the Common Travel Area. But it’s customs rules for traded goods that remain a sticking point. A no-deal Brexit would mean new customs requirements on goods like chemicals and animals or animal products originating from outside the EU.

This would only affect goods going into Northern Ireland from Ireland; it’s unclear how the EU would apply the measures for goods going in the other direction, according to Full Fact, a U.K. fact-checking organization.

Experts disagree on how much of an effect, if any, McKee’s killing or Brexit will have on further political violence in Northern Ireland. Although violence stemming from dissident paramilitary groups in the country is nowhere near as high as it was during the Troubles, it has been a sporadic occurrence since before the 2016 Brexit referendum.  

“The tragic murder of Lyra McKee won’t affect the ongoing Brexit negotiations,” Erik Tillman, a DePaul professor of political science who specializes in international relations, said. “All the parties involved were united in expressing grief and outrage at the killing.”

Jennifer Todd, a professor of politics at University College Dublin, agrees that McKee’s death probably won’t affect Brexit negotiations.

“The British government is obsessed with internal party affairs,” she said. “This will pass from minds quickly.”

In Northern Ireland, the power-sharing administration between the main Protestant and Catholic parties has been suspended for the past two years because of political disputes. But on Friday, Irish Prime Minister Leo Varadkar and British leader Theresa May announced that a new round of talks with all of Northern Ireland’s main parties would take place after the country’s local elections next week.

Separately, the Brexit deal has been pushed back multiple times already, with Parliament repeatedly rejecting the withdrawal deal negotiated by May, Brussels and EU leaders.. The possibility remains that the U.K. won’t leave the EU at all.

Regardless, experts are skeptical that the chaos surrounding Brexit is the sole cause of the recent uptick in violence in Northern Ireland.

“These [paramilitary] groups were around before Brexit and unfortunately they will continue to be,” said Mary McCain, director of DePaul’s department of Irish studies.

Still, McCain is concerned about what Brexit will mean for the Good Friday agreement. She said that while she doesn’t foresee a return to the “catastrophic levels” of violence that happened during the Troubles, people didn’t expect that violence before it occurred then either.

“Trying to find a way for the border to be frictionless will require an agreement between the EU and the U.K.,” she said. “A no-deal Brexit may make certain groups feel like it’s okay to use violence.”

Tillman, the political science professor, said he believes the uncertainty surrounding Brexit and the possibility of a return to violence are largely unfounded.

“There is a broader commitment now among the responsible parties to maintain a peaceful and just political settlement in Northern Ireland than before the Troubles,” he said. “The dilemma for the British government is more a question of what it wants to give up to achieve a Brexit that maintains the Good Friday agreement.”

McCain said that the militants who fired their guns bear full responsibility for McKee’s death, and she hopes that it will push people across the political spectrum, the majority of whom she said are working to bring about peace, to find solutions.

“My hope from this senseless act would be a renewed sense of purpose from political leadership,” she said. “I hope they will focus on what is at stake.”