Officer Edward Dellmore succumbed to injuries received in May 1908 when he was attacked by a prisoner. During the altercation the prisoner punched and kicked Officer Dellmore in the head and stomach. After the assault Officer Dellmore complained of stomach and head pains but continued working. On October 13, 1908 he became ill and passed away twelve days later. His death was determined to be caused by a blood clot on the brain and abdominal abscess.

At the time of his death had been with the agency for 13 months, joining in September 1907. He was survived by his wife and two children. Interred: New St. Marcus Cemetery, St Louis, MO.