On February 10, 1924, Sheriff Blum was shot and killed while investigating a report of a drunk and disorderly man near the railroad tracks, not very far from the site of the current jail in Mexico, Missouri. The intoxicated suspect was reported by a railway worker to be shooting out switch lights in the railroad yard. The suspect also confronted a woman he accused of stealing coal, cursed at her and ordered her to go home. Sheriff Blum responded and took the suspect by the arm. The suspect produced a .38 caliber revolver both he and the sheriff fired their weapons about four times. A witness reported that the suspect pushed the sheriff's gun away each time he fired. The suspect then fled northbound on foot and the Sheriff Blum sank to his knees and died at the scene from a gunshot wound that pierced his heart.

Sheriff Blum's killer, Jim Crump, was apprehended and taken to St. Louis for safekeeping. Crump was first tried and found guilty of 1st degree murder in Audrain County in April 1924 and sentenced to hang. The Supreme Court overturned his conviction based on the jury not being provided with instructions on a verdict of 2nd degree murder as well as 1st degree murder and remanded back to the court for retrial. When Crump was arraigned in Audrain County in January 1925 for his second trial he was granted a change of venue to Montgomery County. He was placed on trial in Montgomery County in February 1925, found guilty and sentenced to death a second time. The Supreme Court affirmed Crump's second murder conviction and he was hanged by the Montgomery County sheriff in Montgomery City on July 17, 1925.

Sheriff Blum was first appointed as a deputy by Sheriff James G. Ford in 1916. He was elected sheriff in 1920 and took office January 1, 1921. He was a widower and the son of John Blum, born in Germany, and Louisiana Blum. He was survived by his brother Ernest and sister Leona. Sheriff Blum's brother, J. Ernest Blum, was sworn in as sheriff immediately following the murder. Interred: Midway Christian Church Cemetery Mexico, Missouri.