Diesel fuel at two gas stations, one in St. Cloud and another in Waite Park, were purposely contaminated in an act that not only ruined hundreds of thousands of dollars in the business' fuel supply but damaged dozens of vehicles that filled up.

The acts of suspected sabotage occurred in underground storage tanks at First Fuel Banks locations on Lincoln Avenue SE. in St. Cloud and 5 miles to the west at Division Street and 15th Avenue N. in neighboring Waite Park, police said Tuesday.

No arrests have been made, and neither police nor company CEO Jim Feneis have determined a motive for what he termed "a vicious attack." Feneis said he's unaware of anyone who would want to harm his business.

A total of 59 vehicles -- some owned by the city of St. Cloud and others privately -- have been affected by the tainted fuel, Feneis said. Primarily, the vehicles experienced loss of power as their exhaust systems started to fail.

Police have estimated the harm done to the vehicles in the tens of thousands of dollars, while Feneis said his company had to dispose of 55,000 gallons of diesel valued at more than $200,000. He said his business has insurance on its losses.

Assistant Police Chief Susan Stawarski said the contaminations occurred sometime between Aug. 16 and Aug. 20. Stawarski said there is no video surveillance available to help the investigation.

Feneis said he has hired a private investigator to assist the St. Cloud and Waite Park police departments.

Testing is being conducted to determine what was used to spike the tanks. Feneis said the early suspicion points to liquid fertilizer.

It's not difficult for anyone to gain access to the underground tanks, Feneis acknowledged, given that "very few [stations] lock their tanks" because the locks are prone to "corrode and are hard to unlock."

"This is probably going to be a game changer for the industry," he said. "We're going to have to come up with a [better] locking mechanism."

Feneis said that among the affected vehicles were two owned by his company. "Isn't that a real poke in the eye?" he said.

A total of $6,000 in reward money — most of that from First Fuel Banks — is being offered for information that leads to an arrest and conviction in this case. Anyone with information about the case is urged to call St. Cloud police (1-320-345-4444), Waite Park police (1-320-251-6300) or CrimeStoppers (1-800- 255-1301).

First Fuel Banks operates five stations -- four in St. Cloud and one in Waite Park. Unlike conventional stations, this chain offers customers the opportunity to prepay for gasoline and lock in the price.

Paul Walsh • 612-673-4482