A Georgia golf pro was gunned down on the course where he worked because he stumbled upon a crime in progress, police said Tuesday.

       Eugene Siller was shot in the head on Saturday on the green of the 10th hole at Pinetree Country Club in Kennesaw, near Atlanta, the Cobb County Police Department said.

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       Two other men were found shot dead in the bed of a white Ram 3500 pickup truck that was on the green, police said.

       Police said Tuesday that they believe Siller was shot because he was a witness who "happened upon a crime in progress involving the unknown suspect" and the two victims in the truck.

       WSB-TV

       Cobb County Police at the scene of the shooting death of pro golfer Gene Siller at Pinetree Country Club in Kennesaw, Ga., July, 3, 2021.

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       No arrests have been made but police said Tuesday they're following "active leads."

       The victims in the truck don't appear to have any connection to the country club, police said. One of the men was the truck's owner, Paul Pierson, and the second victim hasn't been identified, police said.

       WSB-TV

       People pay their respects at the scene of the shooting death of pro golfer Gene Siller who was shot and killed on July, 3, 2021 at Pinetree Country Club in Kennesaw, Ga.

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       A motive isn't clear, police said.

       Police added that they don't believe there's an active threat to the public. Anyone with information is asked to contact the police at 770-499-4111 or at cobbpolicecrimetips@cobbcounty.org.