SANTA ROSA (CBS SF) – A Michigan man who was convicted in September of the second-degree stabbing murder of a man at a marijuana grow in Sonoma County was sentenced Wednesday to 15 years to life in prison.

A jury deliberated less than five hours before convicting Arent Julius Bradt, 36, of killing a co-worker at the marijuana grow on state Highway 128 in Knights Valley near Geyserville on Nov. 24, 2016.

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Bradt found work on the marijuana grow a month after moving from Michigan to Santa Rosa. When Cesar Gonzalez-Rivas, 44, a Venezuela-born co-worker, told Bradt his services were no longer needed, Bradt stabbed Gonzalez-Rivas once in the neck and 17 times in the back, prosecutors said.

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A witness heard the argument between the two men and called 911 when he saw the blood on Gonzalez-Rivas. A Sonoma County sheriff’s deputy arrested Bradt, who was still on the property.

According to the District Attorney’s Office, Bradt said in an interview with sheriff’s office investigators after the attack that Gonzalez-Rivas “ran around bleeding and, like, he didn’t seem like he was ever gonna fall over.”

Bradt’s prosecution included doubts and testimony regarding his mental competence. He also was sentenced to one year in prison for use of a knife.

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