Hundreds of people marched in Seoul last month at a hundred days’ memorial protest marking April’s Sewol ferry disaster, in which 304 people died and 10 are still missing. (Shin Woong-jae/For The Washington Post)

Kim Yung-oh is not exactly sure how much weight he has lost. But when he undoes his belt buckle, his pants bunch around his concave belly. Twenty pounds, he estimates.

Kim, whose 16-year-old daughter was one of 304 people who died when the Sewol ferry sank in April, will on Wednesday enter the 24th day of a hunger strike — staged on Gwanghwamun Plaza, a wide median strip along a central Seoul boulevard that leads toward the presidential Blue House.

The plaza is also where Pope Francis will celebrate an open-air Mass next week — and Kim is vowing to stay put.

“No matter what, I want to stay here and appeal to the pope,” Kim said weakly during an interview on an elevated platform under a tent on the plaza, part of a protest against perceived government obfuscation over the cause of the ferry disaster.

The pope is scheduled to meet with the Sewol families during his visit, but in Daejeon, a city about 100 miles south of Seoul. Nonetheless, protesters know they have some leverage over President Park Geun-hye’s administration as it prepares for the pontiff’s arrival.

Kim Young-oh, a father of one of victims lost his daughter, Kim Yu-min, and has been on a hunger strike for 23 days straight. (Shin Woong-jae/For The Washington Post)

The April 16 capsizing of the Sewol — an overloaded ferry transporting an estimated 476 people and far too many containers from the mainland to the southern island of Jeju — remains an active tragedy in South Korea.

Ten passengers have still not been found, and Seoul’s City Hall remains a carefully tended memorial — complete with funereal chrysanthemums — to the victims, the vast majority of whom were students from one high school.

‘We want to know how our children died’

On Gwanghwamun Plaza, a few blocks from City Hall, Kim sits on his platform, alongside tents designated for victims’ families, religious figures and other supporters. On Tuesday, a group of Catholic nuns, Buddhist monks and Protestant ministers joined Kim in his hunger strike for the day. Supporters handed out free cups of fresh iced coffee to passersby while a TV screen played footage from video shot inside the ferry, by students unaware of the fate about to befall them.

“We want to know how our children died. That’s all,” said Park Yung-woo, a math teacher whose daughter drowned.

The families are urging the country’s president to set up a special investigative panel with a greater proportion of members appointed by victims’ kin than by the government. But, more important, they also want the panel to have the authority to subpoena information it needs and prosecute people it suspects of wrongdoing.

“The parents want truth from the government,” said Won Jae-min, a lawyer who has been helping the families. “We are asking for an independent body of inspectors to look into this case, and we are demanding the government to give them special legal powers so they are able to investigate.”

Park and her ruling Saenuri Party had vowed to establish an independent commission, and the main opposition party had agreed in principle. But they are divided on the details. The deadlock led to the cancellation of hearings scheduled for this week.

The families are calling for the special panel to be established because Park’s administration is widely accused of bungling its response to the tragedy and not being sufficiently forthcoming with the facts. That has led to rumors of government complicity and a cover-up.

An ongoing criminal investigation has shown that dangerous modifications were made to the ferry — including the addition of an extra floor — and that the ballast water meant to counterweigh the cargo had been emptied out, so as not to alert regulators to the changes.

Adding fuel to the suspicions, authorities took almost six weeks to identify a body they now think is that of Yoo Byung-eun, the 73-year-old owner of the Sewol ferry operator, Chonghaejin Marine, who had been on the run since the sinking.

The decomposed body was found June 12 just two miles from one of Yoo’s houses. Even though the deceased was dressed in designer clothing, police said they initially thought it was a homeless person until DNA tests indicated in late July that it was Yoo.

People wondered why it took so long to identify a man who was the subject of the largest manhunt in South Korean history.

Willing to die for his cause

Park, whose approval rating has slumped since the disaster, criticized police and prosecutors Tuesday for their missteps, noting that they continued searching for Yoo even after the body was found.

“The bungled manhunt resulted in the waste of national resources and severely undermined public confidence in the government,” she said during a cabinet meeting, the Yonhap news agency reported.

At the protest site Tuesday, families handed out pamphlets bearing a photo of a moist-eyed Park expressing remorse for the ferry sinking. The headline read: “Were the president’s tears just lies?” Volunteers urged people to sign a petition calling on the administration to establish the independent inquiry commission.

Throughout, Kim sat on his platform in the sweltering heat, nodding at well-wishers who stopped to bow to him.

A sign on a bib he was wearing marked the number of days he had been fasting and carried an appeal: “Madam President, please bury me next to my love Yu-min if this powerless dad falls and dies.”

“I feel ready to die for this,” Kim said, sitting cross-legged on a gray pillow, his thin wrists resting on his knees. “I feel so sorry that I couldn’t save my daughter that day and that I can’t do anything to bring her back.”