A Minnesota man is accused of crushing his co-worker’s head with a hydraulic grapple while the pair were “f—— around” during a tree-trimming job, killing the 26-year-old co-worker.

Christopher Boone Crimmins, 34, is charged with second-degree manslaughter, accused of operating a truck-mounted hydraulic grapple that closed on his co-worker’s head.

According to a criminal complaint filed Friday in Dakota County, Crimmins told police that he and Tyler Anthony Lynch, 26, were working together in Apple Valley on Thursday afternoon when the two started “f—— around.”

The men noticed the grapple’s shadow and Lynch’s shadow on the ground, and Crimmins began moving the grapple to make it look like it was grabbing Lynch, the complaint says. Crimmins was watching the shadows rather than Lynch himself, it says, and didn’t realize the grapple was closing in on Lynch’s actual head until it crushed it.

Police found Lynch on the ground “with a large amount of blood around his body and a significant injury to his head,” according to the Dakota County Attorney’s Office.

A witness told investigators they saw the grapple hit or pinch Lynch’s head, the complaint says. Crimmins was the only member of the crew with the commercial license to operate the machine, which the team was using to clear branches.

Bail was set at $40,000 unconditional or $20,000 with conditions, the county attorney’s office said Friday.

Crimmins faces up to 10 years in prison if he is convicted.

Crimmins was not listed in Dakota County Jail records Sunday afternoon. Court records were not immediately available, and it’s unclear whether he has an attorney. There was no immediate response at a phone number listed for him Sunday.

He is next expected in court on Sept. 10, according to the county attorney’s office.