The Stoneham Fire Department said that Atherton had just graduated Massachusetts Firefighting Academy on June 10. He grew up in Stoneham and before pursuing firefighting, he and O'Connor were both in the Massachusetts Army National Guard. Atherton was deployed in Qatar from 2012 to 2014 and received eight awards during his National Guard career, including the Army Commendation Medal. Friends say that O'Connor was also deployed overseas.