Barclay studied journalism at university and worked for a period in fashion and beauty journalism as a copywriter in the RTÉ Guide. In 2003, she left the fashion industry to write Darkhouse, the first of two novels featuring NYPD detective Joe Lucchesi. Her second novel, The Caller, was released in 2007, and Last Call in 2008. She won the Ireland AM Crime Fiction Award at the Irish Book Awards for her fourth novel, Blood Runs Cold.
