Rick Sheridan was working in his garage when he heard gunshots, and said he found officers lined up on the bank, shooting at the large reptile.
In a statement, Independence Police said a caller reported that his children had seen the alligator along a creek and his son had shown him the creature.
Police dispatch contacted the Missouri Conservation Department, who said that if the officer did locate the alligator, to go ahead and put it down.
According to the police statement, when police located the alligator in a wooded area, an officer fired two shots before realizing the animal was really made out of concrete.
When police contacted Sheridan, they apologized and Sheridan said he had placed the alligator there to keep kids off his property.
The officers advised Sheridan to use "No Trespassing" signs instead.