Killing someone quickly with a knife

Not an expert, but I'd think slitting the throat would be the surest way to do it. Stabbing, one would have to know just where to avoid bones and score a lethal hit. Unless this man has training in murder and/or anatomy, the throat's the most vulnerable area... plus, if he cut deep enough, she wouldn't be able to scream.

If your character really knows what he's doing he can stab through the back of the neck into the brain stem. Destroying the medulla oblongata is about as instantaneous, quiet and painless as you're going to get.

In Violence: A Writer's Guide, Rory Miller talks about professional killers stabbing people in the kidneys multiple times, quickly, "like a sewing machine." Your killer could put his other hand over her mouth while doing this. She would bleed out almost immediately. Miller also mentions stabbing behind the collarbone from above, to get at the aorta.

If you have a character who has training and is an expert at this - as in, truly expert - you should have no problem.

I'm no expert on knife fighting techniques, but I am a former paramedic and I've seen more than a few knife injuries/deaths. There really is no "instant" death from knife wounds. Unless someone is cut severely in multiple places (like the multiple kidney strikes mentioned above), "bleeding out" can take anywhere from two to several minutes depending on the location and severity of the cut.

As noted above...

The back of the neck, at the base of the skull, upward into the brain stem is pretty much a sure shot and would produce death not from blood loss, but from severing the brain stem. But it requires precision, speed, and hard penetration.

Across the throat is not exactly as fast as Hollywood depicts it, and it's seriously messy. The options are cut blood vessels without cutting the trachea (requires two strokes - one on either side of the neck, not quite as messy, slower death, and if you only cut one side, much slower death), or cut the trachea along with the blood vessels (requires a harder stroke, produces more mess from blood spray with respirations, but it's faster).
Estimated time to fatal blood loss from a severed carotid? About 2 to 3 minutes, but the victim will pass out long before that.

A strike from above/behind that pierces behind the collar bone can hit the aorta. Like the back of the neck, it requires precision, speed, and a hard penetration. It's still going to take a couple of minutes for actual death to occur.

If you only want two hits, the kidney strikes are out. To get the requisite amount of damage and bleeding for a quick death would require multiple strikes in very rapid succession ("Like a sewing machine" indeed - and ew.)

Other ideas...

A trained and skilled attacker who has the element of surprise and the trust of his victim could easily slip a knife between the ribs and pierce the heart. Death is not instantaneous, and unless he really hits the heart, not even certain to cause death if the person has access to modern medicine. Two hard strikes directly into the heart would cause lots of bleeding, but it's still going to take a few minutes for death.

Cut both femoral arteries and you're looking at 4 to 6 minutes before fatal blood loss occurs, and the victim will pass out long before that.

From behind a knife in the lower third of the rib cage area can pierce and deflate a lung, seriously limiting the ability to scream. Its still a strike that will require significant force or a helluva shot, missing bone altogether. If the killer hits bone enough force is needed to push the knife further in as the knife will actually gouge the bone as it goes. The stabee would most likely start sinking to her knees opening up a clean shot for that collarbone area mentioned above.

Something else to consider is the length of the knife. Your killer character isn't going to get to the aorta with a standard 3 or 4" boot knife and anything bigger starts creating concealment problems. You may need to use a strategic alternative weapon like an 8" ice pick up a sleeve.

Like others have said, you'll need to write this based on who your character is. He would need a firm grasp of anatomy in order to know exactly how to stab someone and have them die quickly. Even then, the knowledge wouldn't necessarily make him capable of doing so.

Anyway, cutting someone's throat isn't as easy as Hollywood makes it.
About twelve years ago, one of my cousins went to sell some car stereo equipment to two guys he thought were friends. Turns out, they were initiates in some local gang, and they had to kill someone to be brought in. They stabbed, sliced, and beat my cousin. Then they shoved him to the ground and one of them cut his throat. They left him for dead, but he got up, walked to a house nearby and got help.
Cutting the throat requires a great deal of pressure. Skin is tougher than most people think. Arteries too.
And people also underestimate how much blood a person can lose. My cousin lost a great deal of blood but could still walk to get help.

In old battles, the immediate death count was usually quite light, but that's because it would take a lot of the casualties several days to die from wounds inflicted by edged weapons.

Severing an artery is a pretty good way to make someone die, but it won't be instantly. A hit to the groin, armpit, or neck, and the person will almost certainly bleed out without near-immediate medical attention.

Hitting the kidneys would also almost certainly kill your victim, but it wouldn't be instantaneous.

A strike up through the back of the head, where the spine meets the skull would be the fasted and quietest method, but your killer would need the right weapon.

The type and size of knife would be a crucial factor, methinks.

caw

A lot depends on the 'fight' in the victim. Some people have 'died' (or at least permanently lost consciousness) at the first strike to something major, even fairly immediately. Others have finished fights, had a drink and made it to hospital after severe injuries to major organs. The will to live in some people borders on the supernatural, and yet, others, seem almost desperate to leave their bodies, or at least fall into shock/unconsciousness at the first sign of trauma. You can get away with a lot here, i mean, assuming it fits your character. If you just need a victim to die quickly thats fine. If you need that victim to paint half the street red with blood and save the day first, that might be fine as well.

If you follow criminal proceedings, one thing you'll see is the occasional killer saying something like, 'Yeah, it wasn't like on TV at all...' People trying to emulate all these quick and neat assassinations, and almost always doomed to messy failure. I've red about guys that spent a LOT of time and effort, trying to snap some poor kids neck, 'like in the movies'. Walk up and twist the head till the neck snaps. Nope. They cranked on that poor kid's head for minutes. They ultimately had to beat him to death with rocks. Others thinking they could just cruise up behind someone and drop them cleanly with a single stab wound. Nope. Big, loud, sticky mess. The stab through the brain stem gets used a lot in movies, but i'd wager that the pro that could pull this off more times than not is exceedingly rare.

I remember, ages ago, watching some TV program about the evolution of killing technology, and specifically, swords. From the blunt and rough bronze gladius type stuff, to the modern and 'utterly perfect' rapier. 'No need for armor when you can just stab a man through the heart with a 3ft icepick, and drop him like a sack', it touted. Again... NOPE. So much 'Holy-wood' myth out there.

Blades will always be messy, and almost never immediate, unless your killer is true Hollywood elite, or incredibly lucky.

My vote would be for a quick, vicious ear to ear slash, or two. You get it all, blood, air, voice, and there's no fixing it. Takes some strength, conviction and command (the real difference between elite killers and amateurs), and its messy, but dammit... it is DONE. Poor girl...

I know you want to use a knife, but if he's a trained killer wouldn't snapping her neck be a better option?

Severing the Carotid arteries will bring on instant unconsciousness from the drop in blood pressure, and death will ensue shortly. Whether both could be done in one stroke depends on the knife and the skill of the killer and on the size and shape of the victim.
https://en.wikipedia.org/wiki/Common_carotid_artery
If the victim is of average build, then a large, heavy, and very sharp knife could sever both sides in one slash, especially if the blade is long.

If you want to minimize pain and suffering, then slashing the carotids is the way, because unconsciousness would come very quickly. When blood pressure on the brain drops to zero, unconsciousness is instantaneous.

"Compressing both can cause a loss of consciousness in 15 to 20 seconds and death in 2 to 4 minutes."
https://writersforensicsblog.wordpr...meone-to-die-from-carotid-artery-compression/

And that's from compression, rather than severing. There probably are places online that have the information about severing, but I couldn't quickly find one.

A knife can - but it would take a very hard thrust. That's why his experience/training is so important. At the soft spot near the base of the skull, with the right kind of tool and accurate/deep strike - yep.

BUT... based on your last post, I agree with King Neptune - the carotids are a better choice.

If this is a mercy killing, the carotids will produce a fast reduction in blood pressure and extremely rapid unconsciousness, followed by death. (yep - just a few minutes).

The Skeptical Juror has an interesting post on bleed out from a carotid - http://www.skepticaljuror.com/2012/04/cases-involving-severed-carotid_08.html - several actual cases are cited there.

There is also some interesting research posted here: http://www.realfighting.com/unconsciousness_and_death.php (read past the first few paragraphs that discuss inaccurate statements of mere seconds until death).

And just for giggles and grins - set a timer for two minutes and just sit still until the timer goes off. Two minutes can feel like either an eternity, or the blink of an eye.

If your perpetrator is unseen behind the victim, he only needs a single two-stage stroke for a quick death. Assuming a blade length of 6''/15mm+, a hilt-deep straight stab to the side of the neck, just forward of the spinal column thereby missing the bone impediment of the vertebrae, followed by a forward thrust of the cutting edge through the softer tissues and exiting the front of the throat will typically severe both sets of carotid arteries (inner and outer), and both jugular veins. The throat ripped open, the victim will be instantly incapable of speech or further resistance beyond a mere moment--a state of shock is almost immediate. Trust me, that'll do it.

FWIW, the stabbing thrust to sever the brain stem and/or injure the medulla oblongata is far more difficult to master than most think, and is easy to botch. Going for the softer, yet nonetheless critical infrastructure tissues of the throat is typically more effective--and silent.

Ironmike's technique is excellent, especially if the victim is heavily muscled. With pencil necked person a slash from side to side would work, but the stab would be more certain.

keep in mind that the OP is looking for a merciful death, not quite as violent as an assassination.

A few people brought up "snapping her neck" as a solution. Breaking someone's neck isn't as easy as you would think it is. Certainly not as easy as Hollywood makes it seem.
The typical method of twisting someone's head until you hear the celery snap (that's the actual sound effect they often use) doesn't work. Oh, you'll get a cracking sound, but it would take an incredible amount of force to twist the head around enough to cause any damage. You'd be more likely to relieve tension than cause death. Chiropractors twist heads more than they do in movies and people don't end up paralyzed.

The spinal column is quite flexible and stronger than movies make it seem.

Oh but those 105lb waifs in the movies make it look so EASY.

This demands some research. I'm gonna go out tonight and wander around downtown. See whats up...

culmo80 said:

A few people brought up "snapping her neck" as a solution. Breaking someone's neck isn't as easy as you would think it is. Certainly not as easy as Hollywood makes it seem.
The typical method of twisting someone's head until you hear the celery snap (that's the actual sound effect they often use) doesn't work. Oh, you'll get a cracking sound, but it would take an incredible amount of force to twist the head around enough to cause any damage. You'd be more likely to relieve tension than cause death. Chiropractors twist heads more than they do in movies and people don't end up paralyzed.

The spinal column is quite flexible and stronger than movies make it seem.

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But after the trachea and the muscles on the front of the neck have been slashed through bending the neck back to the point og breaking would be easy; it would also be unnecessary.

Military training is hand over mouth, upper thrust under rib cage to lung and heart area using a large knife, Marine Kabar is standard. Second is hand over mouth, downward thrust through throat to aorta and down to vital arteries, sawing motion down through breast bone through heart area. Third is hand over mouth, upward thrust under side of chin (preferably victim's left but not common from behind with right-handed attacker) and back toward center of skull, severing jugular/carotid and piercing brain. Fourth is hand over mouth, multiple quick thrusts through kidneys.

All are kill techniques and all result in silent kills to keep from alerting others. Slashing across the throat is not recommended, not because of its inability to silence or kill, but because of the high potential for the attacker to wound themselves.

Jeff

culmo80 said:

A few people brought up "snapping her neck" as a solution. Breaking someone's neck isn't as easy as you would think it is. Certainly not as easy as Hollywood makes it seem.
The typical method of twisting someone's head until you hear the celery snap (that's the actual sound effect they often use) doesn't work. Oh, you'll get a cracking sound, but it would take an incredible amount of force to twist the head around enough to cause any damage. You'd be more likely to relieve tension than cause death. Chiropractors twist heads more than they do in movies and people don't end up paralyzed.

The spinal column is quite flexible and stronger than movies make it seem.

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The right way to snap a neck isn't to the side, it's a sudden powerful jerk upwards, like a properly executed hanging. The idea is to dislocate the cervical vertebrae, breaking off the second vertebra's protuberance, the dens, and drive it into the medulla oblongata, destroying it and instantly killing the person. It's not easy to do. But twisting the head to the side looks cooler, I suppose.

Blinkk said:

@asroc and @RKarina, and everyone else who mentioned cutting the brain stem, can a knife cut through a brain stem? For some reason I thought that was a difficult thing to sever with only a knife. How much force would a person have to apply to do it correctly? What kind of knife would they need? It would have to be incredibly sharp, right?

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The medulla itself isn't particularly difficult to destroy. It's just nervous tissue, kind of sponge-like, doesn't put up much resistance. The problem is that since it is comparatively fragile and absolutely vital, it's pretty well protected. So in order to injure it the stabber needs to hit the exact right spot, or he's going to hit bone. A slender stiletto-type knife would be best for this, but this method is probably more likely to be used by someone with experience. A casual knife-wielder would probably feel more at home cutting the throat. Just make sure he cuts good and deep and uses a sharp knife; the sternocleidomastoid can be a tough muscle and the carotid sheath is deeper than most people think.

Jeff is right about the military training (using both hands--one clamped over the mouth and the other deploying the blade). I understand that is still the standard instruction taught today. The training I previously referred to is a more specialized technique, only requiring one hand.

There's more to it, of course, but I'm not going to go into detail. The responses you've received thus far should be sufficient to ground your scene in plausibility.

Knock her over the head, grab hair, cut throat and lower to ground.