Police interrupted a bank robbery and fatally shot a ski-masked man who was holding a gun to an employee's head. Two other robbers escaped with another hostage who was later found unharmed.

Police were called by a repairman who had been working on an automatic teller machine at a Sovereign Bank across from Princeton University Thursday night. He told a 911 operator that he saw the employee behind the counter with her hands bound.Officers arrived and encountered a ski-masked, rubber glove-wearing man walking out of an elevator, holding a woman by the neck and pressing a gun to her head.

When officers told him to drop the gun, he screamed at them and waved the gun, threatening to kill the woman. As he brought the gun back to her head, the officers opened fire, killing him. The employee was not injured.

Two other robbers with another hostage jumped into a car behind the bank and drove away, Police Chief Thomas Michaud said. But they crashed the car, abandoned it and left the hostage.

They then hijacked a second car after pushing its elderly driver out but later abandoned that car, too, Michaud said. Police said they found a large sum of money inside but declined to say how much.

Police were still searching for the other two robbers.