METTLER, Calif. -- On Wednesday, Rural Crime Detectives from the Kern County Sheriffs Department and Rural Crime Detectives from the Madera County Sheriffs Department concluded an eight month investigation into the theft of farm chemicals and farming equipment.

The investigation started when Carlos Cesar Castro, Pedro Flores, Walter Gaspar Mejia and Cornelio Hernadez, all from Fresno County, drove to the farming area of Mettler, Calif. on Dec. 11, 2008 and committed several farm burglaries of farm chemicals, the KCSD reported.

Those four men failed to stop for RCD and were able to flee into the thick fog, the KCSD told ABC23.

Detectives obtained video footage of the four men and later discovered they were all from Mendota, Calif.

Detectives working together with RCD from Kern, Fresno and Madera County conducted hundreds of hours of surveillance on the original four suspects and located two additional suspects who were purchasing the stolen chemicals, the KCSD reported.

In March 2009, detectives said they followed Joel Montalvo from Mendota to Calexico, Calif.

Montalvo was found to be in possession of several thousand dollars in stolen farm chemicals from Kern and Fresno County, the KCSD reported.

Montalvo was arrested and transported back to Kern County on charges of possession of stolen property and conspiracy.

In May 2009, the original four men were arrested on warrants charging them with burglary, possession of stolen property and conspiracy.

On Wednesday, the RCD from Kern and Madera County went to 55 Hughes Rd. in Watsonville, Calif. and served a search warrant at the address for stolen property.

The KCSD said that this is the residence of the last suspect believed to be involved in the investigation.

At the location, detectives say they found more than $500,000 in suspected stolen farm chemicals and several confirmed stolen items of farming equipment.

The suspect at this location told detectives he had purchased the stolen property at flea markets.

At this time he has not been arrested.

RCD will be contacting farmers from the Central Valley who have reported chemical thefts in the past several years in an attempt to return the farm chemicals.