ST. CLOUD -- A St. Cloud man has pleaded guilty to starting fires which caused more than $2.6-million in damage at the Martin Marietta granite quarry in Waite Park.

Forty-seven-year-old Raymond Curtis had been charged with 18 felony counts. He pleaded guilty to two counts of 1st-degree arson and seven counts of 2nd-degree arson. The remaining nine charges will be dropped at a sentencing hearing on July 22nd.

A Waite Park police officer spotted smoke coming from inside the gates at the quarry in the early morning hours of April 12, 2015. The officer discovered several fires inside dump trucks, loaders, buildings, and other vehicles. A large fuel tank was discharging diesel fuel onto the ground and into an open pond, conveyor belts were cut, storage trailers burned and oil plugs removed from rock crushers causing oil spills.

Evidence at the scene included several small plastic Gatorade bottles with gasoline and a paper wick, missing padlocks, and missing blueprints.

Interviews with several employees determined Curtis was a likely suspect because he was a longtime employee who had been fired in recent months. Employees said Curtis had extensive knowledge of the plant, always seemed upset with the company, and made threatening comments about the company.

Authorities say they discovered a small Gatorade bottle in Curtis' garbage which matched the production number and expiration code from a partially burned bottle at the scene of the fire and a padlock with a matching key latch was found in his SUV.

A woman eventually came forward who said Curtis was upset at the company for firing him and wanted revenge. Records show she gave police details matching the materials used in the crimes and his plans for carrying them out.

The Stearns County Attorney's Office will argue for a 10-year prison sentence at the July hearing.