A belated memorial service was held in Mokpo, southwestern South Korea, on Saturday for a high school teacher who died in a tragic ferry sinking in 2014 that took more than 300 lives aboard.

Participants in the service remembered the late teacher Ko Chang-seok who went missing while trying to rescue his students as the Sewol ferry sank off the country's southwestern coast en route to Jeju island on April 16, 2014.

Of the 476 passengers aboard, 295 -- mostly students of Danwon High School in Ansan, south of Seoul -- died, with nine others, including Ko, missing at that time. After the sunken ferry was hoisted from the sea early this year, the remains of Ko and three others were discovered in the shipwreck.