Officer Grogan was shot and killed after responding to a robbery call on Washington Avenue. Officer Grogan of the Twelfth Police District and a bystander, Harvey Hammett, died from wounds received during a payroll robbery at the HS Printing Company at 1531 Washington Avenue at shortly after 4:00 pm. When Harvey Hammett came to his aid, he was also shot and killed. The suspects expected to find a cash payroll but found the employees had been paid by check and only made off with $40 from the safe and $100 collected from the employees who were forced to throw their money on the floor. When Officer Grogan, who heard the alarm being spread by an employee who fled the scene, arrived on the scene one of the suspects cried out that there's a cop, shoot him and gunfire was exchanged resulting in Officer Grogan sustaining a gunshot wound to the heart and one below his right eye. Harvey Hammett, a bystander and brother of a police officer came to Officer Groan's aid and also sustained a fatal gunshot wound to the left side of his chest. He died the next morning at City Hospital. The six suspects fled the scene but were apprehended a short time later and were identified as Maurice Dougherty, Frank Bird, Fred James, William Kirchoff, James Wider, and Leo Sproull.

Officer Grogan had been with the agency for 22 years and was survived by his wife and four children. Interred: Calvary Cemetery and Mausoleum, St Louis, MO.