Minnesota Man Allegedly Killed His 20-Year-Old Coworker With a Sledgehammer

David Bruce Delong, 40, was charged with second-degree intentional murder - with prosecutors indicating an upgrade to first-degree murder was being considered - after allegedly killing his 20-year-old coworker Amber Czech with a sledgehammer at their shared workplace in Cokato, Minnesota, on November 11, 2025. Delong allegedly told law enforcement he had been planning to kill Czech for some time because he “didn’t like her,” triggered by what he described as a “bad look” she had given him on a previous occasion.

The Attack

The incident occurred around 6 a.m. inside Advanced Process Technologies, a company specializing in food and dairy processing machinery. Surveillance footage captured Delong and Czech passing each other without interaction, followed moments later by Delong putting on work gloves, retrieving a sledgehammer from Czech’s workstation, and returning to where she was working. Wright County Attorney Brian Lutes said Delong swung the sledgehammer “horizontally” at Czech while she was standing upright, then followed with four more “very aggressive, violent, forceful swings.” Czech suffered fatal blunt force trauma to the head and was pronounced dead at the scene.

The Victim

Amber Czech had recently graduated from Alexandria Technical & Community College after completing a 10-month welding technology program in 2024. Her father described her as outgoing and hardworking, someone who took pride in her craft and was always willing to help colleagues. After the attack, Delong told a coworker, “I hit her with your hammer, she is by your toolbox, she is gone.”

References: Minnesota Man Allegedly Kills 20-Year-Old Coworker with Sledgehammer Because He ‘Didn’t Like Her’ | David Delong charged with murdering coworker Amber Czech at Cokato plant | Cokato man charged with killing coworker Amber Czech at manufacturing facility