A 22-year-old medical student was found dead in the Han River on Friday after going missing for six days, and his family is awaiting the results of an autopsy to learn how he died.

Sohn Jung-min was last seen asleep at the riverside park in Banpo, Seoul, early on April 25 by his friend, who had also fallen asleep. The two had been drinking together.

An autopsy was conducted at the request of Sohn’s family, as two wounds were found behind his left ear.

Sohn’s father told Yonhap News on Saturday that the National Forensic Service said it had found two lacerations behind the left ear, although they were not the direct cause of death.

“They said his cheek muscles were torn, and his teeth were fine,” he was quoted as saying.

Police said they suspect the lacerations occurred as the body hit objects while drifting in the water, adding that they would investigate further based on the autopsy report. The official detailed results will come out in at least two weeks.

A rescuer and his dog found the body drifting about 20 meters ahead of the water taxi jetty on April 30 around 3:50 p.m.

The water moved upstream on high tide for three days after Sohn went missing, according to the rescuer, Cha Jong-wook.

“The body appears to have drifted back to where he went missing as the tide ebbed,” Cha said.

Sohn fell asleep with his friend after drinking from around 11 p.m. on April 24 until past 2 a.m. the next day at the Banpo riverside park next to the water taxi jetty.

Sohn’s friend called his father at around 3:30 a.m., saying he couldn’t wake Sohn up.

The friend said he had fallen asleep again and woken up at 4:30 a.m. Sohn was missing, and his friend went home alone thinking Sohn had gone home too.

The friend was captured on security camera footage leaving the park alone around 4:30 a.m., but Sohn wasn’t.

Sohn’s parents went out looking for their son around 5:30 a.m. The father wrote on his blog and social media to ask for help looking for his son, and he also hung banners around the area.

Police mobilized a helicopter, drones and boats to search for Sohn.

“It must be found out why he went to the river when he must have been sober to some degree, and why he couldn’t come out of the water when it wasn’t that deep,” Sohn’s father told the Chosun Ilbo.

Sohn exchanged Kakao Talk messages with his mother until about 1:30 a.m., just hours before he went missing.

At 1:50 a.m., Sohn posted a video on Instagram of him and his friend dancing.

By Kim So-hyun (sophie@heraldcorp.com)