Alice is visiting Bob, who is on life support in a hospital, when Mallory comes into the room and tries to disconnect Bob's life support with intent to kill Bob. Is Alice allowed to use force against Mallory to protect Bob? There is no euthanasia law or other law allowing Mallory to disconnect Bob's life support, and Bob is conscious and actively objects, but is not capable of stopping Mallory on his own.

  • 23
    Why not? If use of force to prevent murder is legal then how is your scenario any different? P.S. If Bob is on life support it is unlikely he would be conscious and able to consent or not. Commented May 10, 2023 at 5:14
  • 15
    It looks like a very straight attempt to murder Bob to me. Whether this happens in a hospital by removing life support doesn’t make a difference. Alice can use any proportionate violence to stop Mallory. Killing Mallory and his extended family wouldn’t be proportionate, put anything needed to stop him is.
    – gnasher729
    Commented May 10, 2023 at 5:47
  • 2
    @Someone why would you think this was any different from tampering with the brakes of bob’s car?
    – Dale M
    Commented May 10, 2023 at 6:05
  • 9
    Planting a bomb, sabotaging someone's car, etc etc all involve the murderer doing something with a device that will cause the victim's death some time later, without the murderer "directly damaging" the victim themselves. Hell, technically that's even true of pointing a gun at someone and pulling the trigger. If messing with life support didn't count as murder, we'd need a lot of special case legislation to make sure that all of those other scenarios do.
    – Ben
    Commented May 11, 2023 at 2:38
  • 3
    It's normal instead for murder laws to be broad enough to cover your scenario already, and instead have special-case legislation is used to cover the situations that aren't illegal. (e.g. self-defence, doctors operating in good faith, euthanasia, etc etc etc)
    – Ben
    Commented May 11, 2023 at 2:40

6 Answers 6


It depends on Alice's belief about who Mallory is and what Mallory is doing and whether Alice's force was reasonable.

If Alice is aware that Mallory's action is lawful, then Alice cannot use force to protect Bob. Is Mallory a doctor who is lawfully withdrawing treatment? (You say there is "no law allowing Mallory to disconnect Bob's life support" but I'm not aware of a jurisdiction that requires indefinite treatment regardless of the circumstances.)

If Alice honestly believes Mallory is attempting to unlawfully kill Bob, Alice can use force to protect Bob. Is Bob on life support because of Mallory's previous attempt on his life; is Mallory a hitman, a vengeful spouse or some other person with no lawful reason to kill Bob?

Crown Prosecution Service guidance: Self-Defence and the Prevention of Crime:

Self-defence is available as a defence to crimes committed by use of force.

The basic principles of self-defence are set out in Palmer v R, [1971] AC 814; approved in R v McInnes, 55 Cr App R 551:

"It is both good law and good sense that a man who is attacked may defend himself. It is both good law and good sense that he may do, but only do, what is reasonably necessary."

The common law approach as expressed in Palmer v R is also relevant to the application of section 3 Criminal Law Act 1967:

"A person may use such force as is reasonable in the circumstances in the prevention of crime, or in effecting or assisting in the lawful arrest of offenders or suspected offenders or of persons unlawfully at large." ...

In assessing the reasonableness of the force used, prosecutors should ask two questions:

  • was the use of force necessary in the circumstances, i.e. Was there a need for any force at all?; and
  • was the force used reasonable in the circumstances?

The courts have indicated that both questions are to be answered on the basis of the facts as the accused honestly believed them to be (R v Williams (G) 78 Cr App R 276), (R. v Oatbridge, 94 Cr App R 367).

To that extent it is a subjective test. There is, however, an objective element to the test. The jury must then go on to ask themselves whether, on the basis of the facts as the accused believed them to be, a reasonable person would regard the force used as reasonable or excessive.

  • Indefinite treatment isn't required even for conscious patients who want to continue treatment?
    – Someone
    Commented May 10, 2023 at 14:21
  • 2
    @Someone I should add something like, "indefinite treatment regardless of the circumstances" because there are circumstances when it is lawful to withdraw treatment.
    – Lag
    Commented May 10, 2023 at 14:25
  • 5
    @Lag The OP's questions was: "Is it legal to use force against a person who is illegally trying to disconnect a hospital patient's life support with intent to kill the patient?" How can Mallory's action be lawful if he is illegally trying to disconnect the equipment? Commented May 11, 2023 at 22:06
  • The question reads to me as excluding the first possibility, that Mallory's actions could be construed as lawful. This is emphaised by the sentence you quoted.
    – Noch
    Commented May 12, 2023 at 3:22
  • 5
    The fact that Mallory's actions were illegal doesn't mean that Alice knows this. Her use of force could still be unreasonable depending on the facts she had in her possession at the time.
    – Cadence
    Commented May 12, 2023 at 3:38

It depends a tad in ...

Mallory is staff ordered to shut off Life Support

There are cases where life support can be turned off. The two most relevant cases are:

  • the conscious patient telling the doctor,
  • or the unconscious patient having a Patientenverfügung, that demands no life support is performed.

The moment the patient says so or the properly documented paper is in the hands of the doctors for an unconscious patient, they have to end all life-prolonging measures, and shut off life support - in fact, they are not even allowed to start such measures once they are informed of the wish for it.

In a similar fashion, in the absence of such a document and with an unconscious patient, the next of kin might have the life support shut off at some point if they can make it clear that such treatment is against the patient's wishes.

In Germany, turning off the Life support is not (active) euthanasia (which is illegal) but Behandlungsabbruch (end of a medical procedure), which is defined as the not providing or ending of procedures that could prolong life. Behandlungsabbruch is not a crime, if demanded by the patient or the next of kin can make it clear that it would have been the wish of the patient. In fact, it becomes a crime to not turn off the machines the moment that the wish of the patient not to be kept alive is made clear, either by the patient, his Patientenverfügung, or verified by the next of kin.

Because Mallory is not committing any crime in case he is acting on the Patient's wish (expressed by the conscious patient, unconscious patient's Patientenverfügung or unconscious patient's next of kin in absence of a Patientenverfügung), Alice can't legally use any force against Mallory.

Mallory is just out there to murder

Simple case: yes, she may use a reasonable amount of force to stop Mallory. In fact, she is obligated to assist, as long as she is not in danger from that.

  • 3
    Can Patientenverfügung be retracted if, as stated in the question, the patient is "conscious and does not consent"? Commented May 11, 2023 at 7:09
  • 2
    @ToivoSäwén the patient can rescind it, yes
    – Trish
    Commented May 11, 2023 at 7:25
  • 6
    @ToivoSäwén Not only can the patient retract the Patientenverfuegung, it does not even come into effect as long as the patient is able to express his or her wishes.
    – arne
    Commented May 11, 2023 at 8:48
  • 6
    @arne also next of kin can't override an existing Patientenverfügung, only express the patient's possible wishes in case of lack of one.
    – Trish
    Commented May 11, 2023 at 8:50
  • 4
    Not like in the described situation, but a similar incident actually took place. An elderly lady unplugged her roomates life support twice because she was uncomfortable sleeping with the noise. spiegel.de/panorama/justiz/… Commented May 11, 2023 at 13:47

Alice found Mallory commiting an indictable offence, so Alice can arrest Mallory, using reasonable force. See Criminal Code, s. 494.

  • 2
    Most U.S. jurisdictions would be similar.
    – ohwilleke
    Commented May 10, 2023 at 13:49


The United States has some very robust self-defense laws, which would make Alice's actions perfectly legal. Typically, U.S. self-defense/defense of other laws will cover the minimum amount of force required to prevent a crime from occurring, up to and including lethal force, though because of the U.S. federal nature different states have different laws. New York, for example, requires that the level of force used be proportional to the criminal threat, however, considering the crime is 1st degree murder, lethal force can be used to prevent this type of crime.

In the U.S., it's not uncommon for armed police to remain at hospitals, even outside the door of the patient, especially if they are to be taken into custody (either as an arrest or protective custody... Bob could be a criminal or a witness who a criminal would want to end, as Bob could provide evidence against the criminal targeting him.).

Globally, some of the deadliest serial killers are called "Angels of Mercy" (or "Angels of Death"), who are employees in medical professions or hospitals (doctor, nurses, MediTech's, etc.) who kill patients to end their suffering. For example, Charlse Cullen, a nurse in New Jersey and PA area hospitals, was arrested in 2003 and convicted of the murder of 29 individuals, the earliest proven one occurring in 1988. It suspected that he could be responsible for over 400 additional deaths in his 15 year span, but records are not available to prove conclusively. Compared to non-medical serial killers, Sam Little, who was arrested 2 years later and was active for 20 years longer, was convicted of killing 61 people and is suspected of killing 93. Ted Bundy was convicted on 20 counts of murder and may have killed more than 100 people. The most profolific non-medical serial killer in the world, Colombian Luis Garavito is suspected of killing over 300 people, and was convicted of 193. Angel of Mercy killers, on an average, have a higher suspected victim numbers than non-medical serial killers, as they tend to be active in hospitals and target victims they believe are in pain, seeing as putting them out of their misery (hence the name "Angel of Mercy"). Since their victims are often in serious danger, it's not immediately suspect that they take a sudden turn for the worse. Cullen the investigation that lead to Cullen's arrest was actually detected by a poison control worker that the hospital called, who noticed that chemicals turning up in patients who died in nurses had no business being in those patients based on the scripts.


Not only is it legal: In Germany, Alice is actually legally obliged to do anything that can be reasonably expected from her in order to stop Mallory. § 323c StGB states:

(1) Wer bei Unglücksfällen oder gemeiner Gefahr oder Not nicht Hilfe leistet, obwohl dies erforderlich und ihm den Umständen nach zuzumuten, insbesondere ohne erhebliche eigene Gefahr und ohne Verletzung anderer wichtiger Pflichten möglich ist, wird mit Freiheitsstrafe bis zu einem Jahr oder mit Geldstrafe bestraft.

(Anybody who does not render assistance in cases of grave danger or an emergency, even though it is necessary and within reason, will be put in prison for up to one year or will be fined.)

In particular, nobody needs to put themselves in serious danger in order to help. Therefore, if Mallory is armed or is raving mad and smashing things left and right you don't have to put yourself in harm's way (but you should still seek help and alert the authorities).

This legal obligation to render assistance is peculiar to the law systems in the French civil law tradition. By contrast, in jurisdictions in the British common law tradition such an obligation usually does not exist for third parties unrelated to the incident; it only exists for individuals connected to one of the parties or bearing responsibility for the incident.


In the Netherlands you are always allowed to restrain someone and call for the police or authorities... and when is restraining someone violence? Bit of a grey area I think, a lot of ways to interpret it if it comes to a trial...

If it was one of my loved ones that was being unplugged, I would stop that person no matter what punishment followed - deal with that later 😊.

  • 2
    Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center.
    – Community Bot
    Commented May 13, 2023 at 6:59

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .