Brittany Norwood.

Brittany Norwood was arrested Friday and charged with first-degree murder in the death of 30-year-old Jayna Murray, her co-worker at the Lululemon Athletica shop. She’s due in court in Montgomery County on Monday.

Norwood initially told police that two masked men entered the store on the night of March 11 and sexually assaulted her and Murray during a robbery attempt. But police say they’ve concluded that story was a lie and that Norwood killed Murray during a dispute.

Police haven’t yet disclosed a motive, but they say workers at the next-door Apple store reported hearing two women arguing.