Jindo, AP—South Korean President Park Geun-hye said Monday that the captain and some crew members of the sunken ferry committed “unforgivable, murderous behavior” in the disaster, which left more than 300 people dead or missing.

The captain initially told passengers to stay in their rooms and waited more than half an hour to issue an evacuation order as the ferry Sewol sank on Wednesday. By then the ship had tilted so much it is believed that many of the roughly 240 people missing could not escape.

Park said at a Cabinet briefing: “What the captain and part of the crew did is unfathomable from the viewpoint of common sense, unforgivable, murderous behavior.” The comments were posted on the website of the presidential Blue House.

Park said that instead of following a marine traffic controller’s instructions to “make the passengers escape,” the captain “told the passengers to stay put while they themselves became the first to escape.”

“Legally and ethically,” she said, “this is an unimaginable act.”

The captain and two crew members have been arrested on suspicion of negligence and abandoning people in need, and prosecutors said Monday that another four crew members have been detained. Senior prosecutor Ahn Sang-don said prosecutors would decide within 48 hours whether to ask a court for arrest warrants for the four—two first mates, a second mate and a chief engineer.

The captain, Lee Joon-seok, 68, has said he waited to issue an evacuation order because the current was strong, the water was cold and passengers could have drifted away before help arrived. But maritime experts said he could have ordered passengers to the deck—where they would have had a greater chance of survival—without telling them to abandon ship.

Video showed that Lee was among the first people rescued. Some of his crew said he had been hurt, but a doctor who treated him said he had no fractures and only light injuries.

Lee spoke of “pain in the left rib and in the back, but that was it,” Jang Ki-joon, director of the orthopedic department of Jindo Hankook University. Jang said he did not realize Lee was the captain until after he treated him.

Many relatives of the dead and missing also have been critical of the Park administration, angry over the search and rescue response and mistaken assurances in the early stages that loved ones were alive. On Jindo island, near the sunken vessel, about 100 relatives marched for six hours on Sunday, intending to travel to Park’s office 250 miles (400 kilometers) away, before police stopped them. Families also blocked the prime minister’s car and cursed at and pushed the fisheries minister.

So far 64 bodies have been recovered, and about 240 people remain missing. About 225 of the missing and dead are students from a single high school near Seoul who were on their way to the southern tourist island of Jeju.

As divers increasingly make their way into the submerged ship, including a new entryway through the dining hall Monday, there’s been a big jump in the discovery of corpses. And that means that on Jindo, an island near where the ferry sank, relatives of the missing must look at sparse details such as gender, height, hair length and clothing to see if their loved ones have been found.

There are no names listed as relatives huddle around white signboards to identify bodies from the sunken ferry—just the slimmest of clues about mostly young lives now lost. Many favored hoodies and track pants. One girl painted her fingernails red and toenails black. Another had braces on her teeth.

“I’m afraid to even look at the white boards,” said Lim Son-mi, 50, whose 16-year-old daughter, Park Hye-son, has not been found. “But because all the information is quite similar, whenever I look at it, my heart breaks.”

Relatives have already lined up to give DNA samples at the gymnasium where many of them are staying, to make bodies easier to identify when they are recovered.

A transcript released by the coast guard Sunday shows the ship, which carried 476 people, was crippled by confusion and indecision well after it began listing on Wednesday.

About 30 minutes after the Sewol began tilting, a crew member repeatedly asked a marine traffic controller whether passengers would be rescued if they abandoned ship off South Korea’s southern coast.

That followed several statements from the ship that people aboard could not move and another in which someone said that it was “impossible to broadcast” instructions.

An unidentified official at Jindo Vessel Traffic Services Center told the crew that they should “go out and let the passengers wear life jackets and put on more clothing.”

“If this ferry evacuates passengers, will you be able to rescue them?” the unidentified crew member asked.

“At least make them wear life rings and make them escape!” the traffic center official responded.

“If this ferry evacuates passengers, will they be rescued right away?” the crew member asked again.

“Don’t let them go bare—at least make them wear life rings and make them escape,” the traffic official repeated. “The rescue of human lives from the Sewol ferry . . . the captain should make his own decision and evacuate them. We don’t know the situation very well. The captain should make the final decision and decide whether you’re going to evacuate passengers or not.”

“I’m not talking about that,” the crew member said. “I asked—if they evacuate now, can they be rescued right away?”

The traffic official then said patrol boats would arrive in 10 minutes, though another civilian ship was already nearby and had told controllers it would rescue anyone who went overboard.

Ahn said Monday that a number of Sewol crew members, but not the captain, took part in the conversation.

The cause of the disaster is not yet known, but prosecutors have said the ship made a sharp turn before it began to list.

More than 170 people survived the sinking of the Sewol, but the confirmed death toll climbed over the weekend after divers finally found a way inside the sunken vessel and quickly discovered more than a dozen bodies. They had been hampered for days by strong currents, bad weather and low visibility.

Many relatives of the missing have been staying in a gymnasium on Jindo island, but dozens of relatives have started camping out at the port there to be closer to where the search was taking place, sleeping in tents. A Buddhist monk in white robes stood facing the water and chanted in a calm monotone as several relatives stood behind him, their hands pressed together and heads bowed in prayer.

The Sewol‘s captain was arrested Saturday, along with one of the ship’s three helmsmen and the 25-year-old third mate. The third mate was steering at the time of the accident, in a challenging area where she had not steered before, and the captain said he was not on the bridge at the time.

Senior prosecutor Yang Jung-jin said the third mate has refused to tell investigators why she made the sharp turn. Prosecutors have not named the third mate, but a fellow crew member identified her as Park Han-kyul.