A month after a U.S. court ruled against South Korea’s Kolon Industries Inc. for the theft of trade secrets from American firm DuPont Co., the companies have rekindled their dispute here in South Korea.

Prosecutors said Thursday they are investigating the two companies’ dispute over technology leaks regarding Kevlar, a high-strength fiber mainly used for making body armor.

DuPont filed a complaint with prosecutors, arguing Kolon stole technological information used to make the trademarked synthetic fiber. The production data was allegedly given to Kolon by a former DuPont employee who was later hired by the Korean firm, DuPont was quoted by prosecutors as arguing.

Kolon, in response, lodged a petition accusing DuPont of unfair market practices. Kolon suspects that DuPont’s legal move is aimed at blocking the Korea firm from making inroads to the U.S. market, the prosecutors said.

Kevlar, developed in 1965 by DuPont, is used in applications ranging from bicycle tires and racing yacht sails to anti-ballistic body armor.

In September, a U.S. federal court in Virginia ordered Kolon to pay $919.9 million in compensation to DuPont, ruling against the South Korean firm in the intellectual property theft case. Dupont filed the U.S. suit against Kolon in 2009.

Kolon responded in 2009 also, lodging an anti-trust suit against DuPont in the U.S., but the case is still pending. (Yonhap News)