In a shocking incident in Minnesota, a man allegedly attacked and killed his co-worker with a sledgehammer due to personal animosity.

David Delong, aged 40, now faces charges of second-degree murder, as confirmed by the Wright County Sheriff’s Office. The brutal attack unfolded early Tuesday morning before dawn.

The incident took place at the Advanced Process Technologies facility in Cokato, shortly before 6 a.m. Delong reportedly left his work area to approach his colleague. Surveillance footage reviewed by authorities shows Delong, wearing gloves, seizing a sledgehammer from the victim’s workspace and attacking her.

According to the sheriff’s office, Delong swung the sledgehammer horizontally while the victim was presumably standing, though she was out of the camera’s view. He then continued to strike her with the hammer four more times in a downward motion, suggesting she was on the ground at that point.

The probable cause document describes the severity of the crime: “The defendant bludgeoned the victim to death with multiple blows to the victim’s head with the sledgehammer.”

Authorities report that Delong confessed to the killing, stating he “intended to kill the victim” due to personal dislike. He admitted to having planned the attack for some time.

Deputies responded to the worksite to find the woman on the cement floor of the building near her workstation “with very significant head trauma and substantial blood loss.” A bloody sledgehammer was on the floor near her. First responders tried to save the victim, but she died “because of blunt force trauma to her head and corresponding blood loss.”

Delong was quickly identified as a suspect. A witness reported that Delong told him something along the lines of “I hit her with your hammer, she is by your toolbox, she is gone.”

The victim was later identified as 20-year-old Amber Czech, according to Minneapolis-based NBC affiliate KARE. She was remembered as being hard-working, outgoing, and passionate about welding.

Delong was arrested and booked into the Wright County Jail. He faces up to 40 years in prison. Wright County Attorney Brian Lutes said he will review the case to consider whether to convene a grand jury in pursuit of elevating the charge to first-degree murder.

The defendant is scheduled to appear in court on Nov. 24.

Cokato is located about 50 miles west of Minneapolis.