Thank you, ShakeyBrainSurgeonm, for your contributions here.
Doctor, I have three questions for you.
First, let's assume that a diver's air were shut-off and that this diver were held down (presumably by another diver). Wouldn't the diver eventually lose consciousness?
Second, under that hypothetical, approximately how long would it take for the diver to lose consciousness?
Third, if the diver were to pass-out while under water, then couldn't that unconscious diver die due to aspiration of water into the lungs?
Thank you, Doctor.
This all varies according to the individual, but it might take several minutes to pass out, five to ten minutes to suffer irreversible brain injury and ten minutes or longer to actually suffer cardiac arrest. Fit, trained people can hold their breaths for several minutes without passing out; a struggling, panicked amateur will likely pass out much sooner. In young people with normal hearts, cardiac arrest more likely arises from the acidosis from carbon dioxide retention and not from the hypoxia itself. The heart is much better at extracting oxygen, and more resilient, then the brain.
The presence of water in the lungs requires that the regulator be out of the mouth while the person is still taking breaths, and that no laryngospasm occurs. See the excellent book
A Perfect Storm, which has a rather grim and clinical chapter on the physiology of drowning. Some people can drown without scuba gear and still have very little water in their lungs.
To summarize my point: it isn't so easy to kill a young person from hypoxia in a brief time span. Injure them yes, kill them no. But the issue, I guess, isn't what
will happen, but what the perpetrator
thinks will happen.
For a crime, the law requires an action be taken with criminal intent for a crime to be committed; the nature of the intent determines the criminal liability of the act. For example, a woman bakes her new boyfriend a cake made with peanut oil. The man is allergic to peanuts, eats it and goes into shock, eventually dying. The prosecution must prove she knew of his allergy; if she didn't, no crime has taken place, even though her actions lead directly to his death. The act was there, but the intent lacking.
If evidence is found that she knew he was allergic, she might claim that she only intended to make him ill because she was mad at him. If this is true, she is guilty of manslaughter. However, if it can be proven that she knew of prior episodes which were almost fatal to him, it can be argued that she intended to kill him with premeditation. Thus, the same act could be a) an innocent mistake; b) five to ten years in prison; or c) life in prison or even a death penalty, depending upon the mental intent of the person committing the act and their knowledge of the consequences of that act.
Let's assume a person is seen turning off someone's tank underwater, then a struggle ensues, the person sinks to the bottom and the perpetrator swims away "to get help". This could be horseplay, a cruel trick; it might be two misguided numbskulls practicing some sort of air-sharing skills underwater; it might be murder. It all depends on what the perpetrator intended when shutting off the air, and how much that person knew about the consequences of his actions. In this case, the diver's knowledge, training and experience would work against him.
An experienced and highly trained diver would never turn off the air of his buddy in this scenario either as a prank or as a skills test. That leaves intentional injury as the only rationale. To a lay jury, my academic arguments about how long it would take to die would be meaningless. To a non-diving, non-expert, someone shutting off my tank underwater wants to kill me, Period.
In this case,
no one actually saw him turn the tank off, so what action he may or may not have taken is speculative. Consequently, it is going to hard to prove that he had formed an intent to kill her.
This case is, as I have pointed out earlier, identical to several recent cases where newlywed husbands took their wives on hiking/rock-climbing excusions for which the women were ill-prepared. The wives fall to their deaths; in those cases, massive amounts of circumstantial evidence existed (the husbands took out large insurance policies, for example; in one case, the husband took his wife on a canoe trip and allegedly tried to drown her the day before she fell to her death, but she managed to survive that day, only to die the next). Without direct evidence of some physical act by the husband leading to the lethal falls, these men all walked away with not guilty verdicts.
In the case of Scott Peterson, no one saw him murder his wife, either. In that case, however, it was clear she
was murdered. No one winds up bound in tape and floating in the ocean accidentally. In this case, on the other hand, like the cases of the hiking falls, the possibility of an accidental death is there. This possibility, plus the lack of any eyewitness evidence of an actual act leading to her death, leads me to believe that he would not likely be convicted.
The family's recourse here is a civil suit to bankrupt him. That would not require either intent to kill or a guilt beyond a reasonable doubt. One would simply have to prove that he was negligent in taking his wife on this trip and he failed to provide a reasonable amount of effort to rescue her. That should be easy.
