The 40-foot cabin cruiser was carrying about 30 people when it hit a reef off San Diego on Sunday morning, sending a barrage of broken wood ashore in the rough, choppy waters.

As the wreckage of the vessel slowly disintegrated in the ocean, the passengers — who authorities say were probably aboard a human-smuggling vessel — struggled against a powerful rip current and 60-degree water.

About a day after law enforcement agencies scrambled to locate and rescue those on board, the U.S. Coast Guard said it was suspending the search. Three people died, officials confirmed, and 29 others were rescued near Point Loma, a peninsula on the edge of San Diego Bay.

Five of the rescued were taken to a hospital and one remained in critical condition Monday, according to a news release. Authorities had previously reported that four people had died.

In a statement, Capt. Timothy Barelli, commander of the Coast Guard’s San Diego sector, said the incident was a reminder of “how dangerous these ocean smuggling attempts can be.”

“We will continue to work with our local, state and federal partners to prevent, detect and respond to cases like this to keep the waters of San Diego safe and secure,” Barelli said.

A day earlier, U.S. Border Patrol supervisory agent Jeff Stephenson called the ocean “inherently unsafe.” Traversing the sea from Baja California, Mexico, brings its own risks, he said. High surf. Inadequate safety measures. Old, tattered life jackets.

“The smugglers don’t really care about the people they’re exploiting. All they care about is profit,” he said. “To them, these people are just commodities.”

The cause of Sunday’s capsizing is under investigation. Officials said the latest incident underscores the dangers that come as migrants attempt to enter the United States on fishing vessels that traverse the Pacific. As the New York Times Magazine has reported, an increase in border fences and surveillance technology, as well as growing dire economic and crime conditions in Mexico, have driven more migrants to try the ocean route.

Although these maritime attempts ballooned during Donald Trump’s presidency, they now present an enforcement challenge for President Biden, who is also contending with how to best handle a rising number of migrant families and children running from poverty and violence in their home countries.

From fiscal 2019 to 2020, Border Patrol officials reported a 92 percent increase in apprehensions at sea, Stephenson said, with this year on track to reach similar numbers.

Just days before the incident, law enforcement officials had warned about the increase in smuggling vessels in the San Diego area, saying they would be increasing efforts to warn migrants about the risks of trying to enter the U.S. by sea. Last week, CBP said its maritime and air agents had stopped a small wooden boat that had been traveling without navigation lights and carrying 21 people on board.

Shortly before 10 a.m. Sunday, authorities received reports from a commercial vessel that another boat appeared to be in trouble, veering close to the surf line near the Cabrillo National Monument.

Authorities sent a rescue boat, initially believing based on the call that only one person was on board the 40-foot cabin cruiser. But once officials arrived at the scene, the vessel had broken apart.

“The boat was on the reef bouncing back and forth and then just slowly disintegrated into a bunch of pieces,” Lifeguard Services Lt. Rick Romero, of San Diego Fire-Rescue, said at a Sunday news conference. “There’s no boat there. It’s all debris.”

Instead, officials found about 30 people scattered around the peninsula — some onshore needing CPR or suffering injuries, and seven who were found in the water, fighting a rip current or already drowned. Around them was a “large debris field” of wood and other material that had split apart.

Authorities said they had identified the operator of the boat, who was in custody and communicating with agents. The Coast Guard has not identified the names or nationalities of anyone on the boat.