Sheriff Dierker was shot and mortally wounded when he attempted to arrest a suspect for assault.

Sheriff Dierker was shot and fatally wounded by a man he attempted to arrest for trying to shoot another man over a dispute about wages. The suspect ran into a home and fired a shot at his former employer. The sheriff was called and was able to track the suspect to a barn using bloodhounds. Sheriff Dierker and Deputy Ollendorff approached the barn and the suspect fired on them and they returned fire. Sheriff Dierker sustained a gunshot wound to the stomach and as Deputy Ollendorff approached him he was also shot in the legs with a shotgun blast. Hours later an angry mob trapped the suspect in the hayloft of a barn. The suspect set fire to the barn in an attempt to escape but as he entered the barn door he was shot twelve times throwing his body into the burning barn.

Sheriff Dierker was taken to St. Joseph's Hospital where he died a few hours later.

Sheriff Dierker was nearing the second of two four-year terms as sheriff of St. Charles County, he served from 1904 to 1908 and from 1912 until his death. He was survived by his wife who he had been married to for only six weeks. Interred: Wentzville, Missouri