Three Hannibal men pleaded guilty to illegal dumping in Ralls County, Mo.
In May 2013 the Ralls County Sheriff's Office launched a two-month investigation into several incidents of old tires being dumped in the county.
Lester D. Hirner, Michael R. Hirner and Dustin Smith were arrested and charged with criminal disposition of solid waste.
A Ralls County circuit judge sentenced Lester D. Hirner to four years in state prison and $10,000 fine.
Michael R. Hirner was sentenced to seven years in the state prison.
Dustin Smith received a suspended sentence of four years in the state prison. He will have five years of supervised probation.
If you have any information about illegal dumping in Ralls County you are encouraged to contact the sheriff's office at 573-985-5611.