Underwater Suicide? Mysterious Case of Diver Who Stabbed Himself

There are people in this world who voluntarily swim into underwater caves. Apparently bored with the unlimited supply of breathable air and abundant sunlight God kindly graced us with, these thrill-seekers spend their free time diving deep underwater, sometimes hundreds of feet down, so they can navigate treacherous rock formations with glorified flashlights and limited air supplies.

You'll have to forgive my snark. As a new dad, the thought of taking up such an extreme hobby is disconcerting. Cave divers argue that this "adventure sport" can be enjoyed safely. They follow five golden rules to minimize their risk while exploring these remote environments, and apparently, the views are worth the inherent danger. "I just look at the most raw, harsh piece of nature and I find all the beauty in it," one cave diver said in 2005. "Everything about it is beautiful."

Nevertheless, these divers will insist that you should stay far away from caves if you're not properly trained and equipped. Indeed, a good portion of the expert commentary I reviewed for this story was dedicated to documenting all the horrific ways a cave dive can go wrong. Even experienced divers who do everything correctly don't survive on occasion.

Knife-wielding diver

If you want to understand just how deadly this hobby can be, consider the story of one untrained diver who entered a cave, ran out of air, and then supposedly stabbed himself to avoid drowning. The gory details were recounted in a 2003 case report published in the Croatian Medical Journal. The abstract reads like an episode of CSI:

A scuba diver was found dead at the bottom of an undersea cave at 54.1 m [177 feet] water depth, with a knife protruding from his chest. Autopsy confirmed death due to both drowning and a penetrating knife wound. The incident was first considered a homicide and two suspects were arrested.

Careful forensic analysis of the profile of the diver’s last dive stored in the dive computer, dimensions of the undersea cave, as well as other forensic findings, showed that the case was a suicide, which the diver most probably committed while running out of air, in an attempt to avoid the agony of drowning.

Divers who perish in caves commonly underestimate the amount of air they need to complete their dive. They swim too deep into a cave only to realize their critical mistake once it's too late. So why did this gentleman (referred to as "MK" in the paper) supposedly decide to plunge a knife into his chest? It's hard to say, though a few details may point us in the right direction.

Drunk Diving

One of the many threats divers face is nitrogen narcosis, “a change in consciousness and neuromuscular function caused by breathing compressed inert gas.” Divers call it getting “narced.” The symptoms usually begin around 100 feet as your tissues absorb increasing amounts of nitrogen and get more severe the deeper you dive; they include euphoria, comparable to the sensation of drunkenness, and impaired judgment. Some studies have found that divers may experience a “lack of inhibitory control capacity,” prompting them to react irrationally to dangerous circumstances, such as a dwindling air supply.

Breathing different combinations of gasses (such as oxygen, nitrogen, and helium) while diving can mitigate the effects of nitrogen narcosis. MK wasn't breathing a mixture of this sort, and he was diving at a depth of 114 feet, deep enough to experience some of the symptoms. He also had a blood-alcohol level of 0.114, which would have exacerbated the effects. Research has also shown that divers under stress experience worse narcotic symptoms.

The case report speculated that MK made it to an air pocket somewhere in the cave after getting lost. He didn't have enough air to return to the surface, so, in his altered state, MK deemed a knife to the chest preferable to waiting for an unlikely rescue or drowning.

Homicide?

Another possible explanation is that MK was murdered. Why and how this could have happened are anybody's guess. But a few details point away from murder as a viable explanation. First, as the case report noted, "the scuba gear of the victim was in perfect condition." If you wanted to kill a diver, it seems that sabotage would be an ideal approach. Investigators also took samples of a “reddish stain" found on the boat, suspecting it was blood. It was just paint. Additionally, "no other defects of the suit or other injuries" were found on MK's body. The researchers suggested that such defensive wounds would have indicated that a fight ensued.

Most importantly, the investigators were able to recreate the fatal dive using data stored on MK's dive computer. Had he been stabbed on the boat, his killer would have had to shuttle his lifeless body around the two major areas of the cave (the galleries) to generate the data recorded by the computer. As the researchers wrote:

In that case, the supposed killer(s) would have to throw him overboard immediately after stabbing him, take him to 50 m depth, fake ascent, fake the victim’s wondering [sic] in the shallow gallery, take him to the deep gallery, and finally drop him from the only point from which it was possible to sink vertically from 35 to 54.1 m, ie, from the roof of the deep gallery.

Strictly speaking, this wouldn't have been impossible. One of the other men on the boat with MK was a diver supposedly capable of this feat. But the hypothesis raises an obvious question: Why? The researchers seemed to think there were far simpler ways of committing murder:

If another diver would approach the supposed victim from the back, tear the regulator from his mouth, and hold him ... any diver would drown very soon. No knives or complicated plans would be necessary. A killer could empty the victim’s [air] cylinder manually ... and an investigation, finding no external injuries, would conclude that the victim must have drowned.

Maybe it didn't happen

Alternatively, the entire story might have been made up. At least one certified cave diver, co-host of an engaging show called Dive Talk, took this perspective. After reading the case report, he argued that MK wouldn't have had the presence of mind to precisely calculate how little air he had left, then choose suicide over drowning. Killing himself with a single thrust through the chest would also have been difficult. Croatian military divers who reviewed the case also "rejected the possibility of a suicide."

As fun as it is to speculate, perhaps the details of the case are ultimately irrelevant. It's clear that MK's death was preventable. He shouldn't have gone diving in a cave that was beyond his capability—alone, ill-equipped, and intoxicated. MK could have benefited from the advice comedian Todd Barry gave to people with neck tattoos: "Hey, man, you forgot to not do that."