Four masked thieves tried to rob a San Diego area casino on Wednesday by pulling a display case full of money from the lobby with their sport utility vehicle, police said.

The robbers, armed with guns, entered the Barona Casino lobby in the early hours of Wednesday morning and placed a steel chain around a display case full of money, the San Diego County Sheriff's Department said in a statement.

They hooked the chain to a Ford SUV parked outside the casino and tried to drive away, pulling the case along with them.

It seemed like a very amateur attempt, Detective Sergeant Tom Poulin said. He said the display case was for a promotion to win $250,000, but the case likely contained $100 bills on top of a stack of $1 bills to make it look like a larger amount of money than it was.

One of the robbers shot the display case plexiglass, breaking it open, and the thieves then grabbed an unknown amount of money before fleeing with a roughly 30-foot-long heavy duty steel chain dragging behind their vehicle, Poulin said.

The SUV and a bag full of money were found abandoned roughly a mile from the casino a short while later, police said. The four robbers have not been found.

Department of Justice officials were assisting with the investigation, Poulin said.