BUSAN (Yonhap News) – South Korean crew members of a ship hijacked by Somali pirates last month returned home Wednesday, 13 days after being rescued by the Navy.

The seven crew members, including the ship's first officer, Lee Ki-yong, arrived at Gimhae International Airport, 450 kilometers south of Seoul, earlier in the day and plan to head for the local Coast Guard office to help in the ongoing investigation to prosecute the five captured pirates.

The 11,500-ton Samho Jewelry and its 21 crew members, including eight South Koreans, was hijacked in the Indian Ocean on Jan. 15. They were freed on Jan. 21 after a daring commando raid.

The entire crew was rescued alive – although the captain was seriously wounded – and eight pirates were killed.

The crew members, who looked tired from the long flight, expressed gratitude for the concern and support shown by the public and the government.

Local law enforcement authorities said the testimonies of the crew will be needed to get a clearer picture of how the hijacking took place and the shooting of the Samho Jewelry's captain, Seok Hae-kyun.

The Coast Guard also plans to determine the exact role of the pirates aboard the ship, and whether they mistreated the crew.

The information is to be used against the captured pirates, who are expected to stand trial in the country for piracy, attempted murder and other criminal charges.

Initially, one pirate admitted he shot Seok, but later retracted his statement.

The injured captain, meanwhile, who was brought back late last week to undergo emergency surgery, is in stable condition at Ajou University Hospital in Suwon, south of Seoul. Doctors say his vital signs have improved.

"His vital signs such as blood pressure, pulse and thrombocyte levels have started showing signs of improvement, which is an indication that he has made it past the dangerous stage of treatment," a hospital source said.