(CNN) A 57-year-old woman who was arrested Tuesday in connection with the investigation into the murder of Northern Ireland journalist Lyra McKee was released several hours later, police said.

McKee, 29, was shot in the Creggan area of Londonderry in what police in Northern Ireland described as a "terrorist attack." The prominent freelance journalist had written for publications including The Atlantic and Buzzfeed News.

The city -- which is referred to by Irish nationalists as Derry and British unionists as Londonderry -- is a short drive from the border with the Republic of Ireland.

"A 57-year-old woman arrested this morning by detectives investigating the murder of Lyra McKee has now been released unconditionally," the Police Service of Northern Ireland (PSNI) said in a statement on Twitter on Tuesday evening.

"Detectives from PSNI Major Investigation Team continue to appeal for help from the local community in Creggan or anyone with information."

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