Costa Rica ? A tour bus of U.S. senior citizens defended themselves against a group of alleged muggers, sending two of them fleeing and killing a third in the Atlantic Coast city of Limon, police said Thursday.

One of the tourists – a retired member of the U.S. military aged about 70 – put assailant Warner Segura in a headlock and broke his clavicle after the 20-year-old and two other men armed with a knife and gun held up their tour bus Wednesday, said Luis Hernandez, the police chief of Limon, 80 miles east of San Jose.

The two other men fled when the 12 senior citizens started defending themselves. The tourists then drove Segura to the Red Cross office, where the man was declared dead.

The tourists left on their Carnival cruise after the incident and Hernandez said authorities did not plan to press any charges against them, saying they acted in self-defense.