A Chinese fisherman who was killed by a rubber bullet on Oct. 16 died of a ruptured heart, the National Forensic Service said Saturday.

The NFS said the 44-year-old fisherman, identified by his surname Zhang, suffered a slight fracture to the rib around the area where the bullet hit, and a 2 mm-long rupture in the heart. It added there were no signs of beating or chronic illness.

The Coast Guard raided Chinese trawlers illegally fishing in Korean waters 90 km northwest of Hongdo, South Jeolla Province on Oct. 16. Zhang was among other fishermen trying to prevent the Coast Guard from boarding by brandishing a saw.

He was hit by a rubber bullet fired by a Coast Guard officer, took a few steps, collapsed and died.

The autopsy was originally scheduled for last Thursday, but was postponed twice because China insisted the consent of the bereaved family was needed. Zhang's wife, who arrived in Seoul on Saturday morning, identified his body before the autopsy.

The NFS said there was no indication that excessive force was used. An NFS official who took part in the autopsy said, "The bullet hit Zhang's chest when his heart was full of blood. During the heartbeat, when the heart is filled with blood, even a small shock can lead to heart rupture."

The NFS will carry out chemical and DNA tests and announce the final autopsy results in 10 days. Meanwhile, 11 other fishermen who violently resisted the raid have been arrested.