A sailor has died in three out of the last four Navy SEAL training classes, with one drowning days ago during a pool exercise and another committing suicide in April after failing to complete one of the U.S. military’s most demanding training programs.

A third sailor, who had been drinking heavily, died in November after his pickup truck rolled off the side of the road, less than three days after learning he had just barely missed the cut to continue training.

All three men were trying to complete a grueling six-month course that serves as a gateway into the storied community of Navy SEALs. The training includes a seven-day stretch of little sleep, self-induced hypothermia and brutal physical conditioning known as “Hell Week.” It is here the majority of SEAL hopefuls quit, also known as “ringing the bell.”

The rash of deaths raises questions about the safety of trainees and whether the Navy is providing adequate supervision for the approximately 80 percent of trainees who drop out, leaving many of them despondent after years of hope and preparation and months of intense training.

The Navy defended the safety of its program but said there was room to improve handling those who wash out, particularly sleep-deprived sailors during Hell Week.

“Despite a successful track record, any loss of life drives us to ensure we are doing everything possible to make training safe and effective,” said Captain Jay Hennessey, commanding officer of the Naval Special Warfare Center, in a statement. “Our safety precautions for those who dropped from training have been effective for 50 years.”

On May 6, James Derek Lovelace, 21, died at the Naval Special Warfare school in Coronado, Calif., after Navy officials said he was “having difficulty” during a pool exercise. The San Diego coroner’s office said a preliminary autopsy indicates he drowned. The Naval Criminal Investigative Service is examining the death.

Navy video shows SEAL 'drown-proofing' exercise (Youtube/America's Navy)

Four weeks earlier, Seaman Daniel DelBianco, 23, also a SEAL trainee, took the elevator to the top of a San Diego hotel and threw himself to the street 22 floors below. DelBianco had been in the middle of Hell Week, after 50 hours of no sleep, according to his father.

In November, late one night, Petty Officer 2nd Class Caplen “Cap” Weare’s blue pickup truck was found upside down next to the I-5 highway in San Diego. According to the county coroner’s report, his blood alcohol content was just under twice the legal limit and Weare, who was 24, wasn’t wearing a seat belt.

“I should have been there,” said his mother, Julie Weare, who said her son had wanted to be a Navy SEAL his entire life. “He never would have wanted anyone to take the blame but himself, but I should have been there and he shouldn’t have been out by himself that night.”

The course the men were trying to complete is the initial portion of a nearly year-long Navy SEAL training program, called Basic Underwater Demolition/SEAL training, or BUD/S. The program is designed to weed out those who might not be able to endure the stress of being in combat. It is also supposed to train sailors in the basic skills required to be a SEAL. Candidates need to be in the best shape of their lives and be extraordinarily strong swimmers.

The training exercises are particularly tough because the SEALs are one of the most elite groups in the military, expected to execute some of the military’s most difficult special operations missions — including, for instance, the 2011 raid on Osama bin Laden.

Rare photos show Osama bin Laden while hiding in Tora Bora

Photos have been released of the Tora Bora compound Osama Bin Laden lived in until a Western bombing campaign forced him to flee. Photo credit: U.S. Department of Justice (Abdel Bari Atwan via U.S. Department of Justice/U.S. Department of Justice)

But that means that overall training for these sailors — including those who have already become SEALs — is inherently dangerous. In April 2015, two of the elite special warfare sailors died during underwater physical training near Virginia Beach. In March that same year, SEAL Jason Kortz died in a parachuting accident in California.

It’s unknown how many deaths have occurred among sailors trying to become SEALs, making it difficult to determine if the recent fatalities in San Diego constitute a spike.

BUD/S is a component of Naval Special Warfare Preparatory School, which reports to Naval Special Warfare Command, led by Rear Adm. Brian Losey. A decorated flag officer, Losey was recently passed up for promotion and will soon retire after multiple investigations found that he had retaliated against whistleblowers.

In the past, when trainees dropped from BUD/S, they were sent to a holding platoon, known as X Division. There they performed menial tasks around the base, off-loading supplies and working around the barracks.

“It was a terrible environment with next to no supervision” said Donald Carter, a former BUD/S trainee who dropped during Hell Week in 2008. “You have all these guys who spent their entire lives preparing for this one event and once they couldn’t have it … it was a cesspool of depressed and angry people.”

According to Carter, X Division was disbanded shortly after he left in 2009, forcing those who failed the rigorous training regime to go directly to their new units. It’s unclear whether the Navy currently has a protocol for monitoring sailors who fail to complete training.

Lovelace, DelBianco and Weare had similar backgrounds: They were intelligent, star athletes who desired to become a SEAL since childhood.

“He said it was God’s calling for him,” said Weare’s mother.

Weare called home almost every night. “I knew when he was doing boats, and I knew when he was doing logs,” she said, referring to the different types of physical training undertaken by the sailors.

Weare was on his second attempt through BUD/S after having failed a part of the swim qualification in a prior class, according to his mother. During the second attempt, on the Thursday before Hell Week began, he had trouble with a certain part of a pool exercise but ended up completing it successfully.

“They were gathering their things up from around the pool and the chief that was in charge called him over and said that … he had technically passed, but he couldn’t pass him in good faith,” his mother recalled. “He told the man that held the clipboard to change Cap from a pass to a fail.”

“He told me he didn’t blame the chief, he said he actually liked him,” his mother recalled. “He always took responsibility for himself.”

That day, Weare requested to drop from the course.

Weare had wanted to be a SEAL since he was 8 and joined the Navy in 2010 with that goal in mind. His vision, though, wasn’t up to the SEAL’s standards. Instead he enlisted as a Navy master-at-arms and underwent corrective laser surgery on his own dime — and without the Navy’s knowledge — so he could pass the medical screening required for BUD/S.

His mother said that she spoke with her son after he had dropped from the class the Friday before he died. “I know there was sadness, but he was also looking toward the future,” she said. They texted a little Saturday and that night, after dinner, Weare met up with some friends. He crashed his car later that night.

DelBianco, the sailor who died last month, had built his life around becoming a SEAL. Blonde-haired and square-jawed, he was born in Arlington, Va., and shipped to boot camp after he graduated from the University of Southern California in 2015 with honors, foregoing an officer’s career path because he wanted to be an “operator,” his father, Steve DelBianco, recalled. A varsity rugby player in college, DelBianco was recognized as an Honor Graduate of his Navy recruit class.

In an obituary posted online shortly after his death, DelBianco is quoted on why he wanted to become a SEAL.

“My life won’t feel complete unless I do this,” he wrote. “Every time I read about or see pictures of SEALs, I feel motivated. The experience will shape and define the rest of my life.”

After DelBianco dropped from training on April 5, the Navy said he was directed to a recovery area for a day of observation. But DelBianco decided to leave the base and drove to the Marriott Gaslamp hotel in San Diego, according to the coroner’s report. Just after noon, he took the elevator to the rooftop bar on the top floor, where stayed for hours, even though the lounge was closed. One person saw DelBianco “staring off into the distance,” according to the coroner’s report. At 3:24 p.m., DelBianco jumped over the side of the building. There was no note and his toxicology report was clean, according to the coroner’s report.

His father had also seen him the week before and he “appeared to be doing fine,” said the report.

Following his son’s death, the elder DelBianco asked Admiral Losey, who attended the sailor’s memorial service, to promise that he would reform BUD/S training to ensure that there was proper oversight after a trainee dropped from the class.

“My family’s interested in the Navy making dramatic changes in their procedures and their priorities to care properly for someone who is dropped or drops on request,” his father said. “Especially in the middle of Hell Week … when they are at their most vulnerable, the Navy has the greatest responsibility to look after them.”

Hennessey, the Naval Special Warfare Center commanding officer, said there was an ongoing investigation into the deaths that would outline more specific recommendations. “The Naval Special Warfare Community mourns the loss of all three of these sailors,” said Hennessey.

“I think my son would do it all again if he could,” said DelBianco’s father. “But it’s not right the way they are so careless about the well-being of a guy they’ve taken to the point of breaking and having broken him, to leave him unsupervised.”

Julie Tate contributed to this report.