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Criminal Law
University of California, Hastings School of Law
Lee, Evan Tsen



à The act of doing something that is not socially accepted.

requires a relevant voluntary act or a failure to act where there is a legal duty to act. The criminal law does not punish for evil thoughts alone. Just because you think it doesn’t mean you will do it.

MPC 2.01 – person is not guilty of an offense unless his liability is based on conduct which includes a voluntary act or the omission to perform an act of which he is physically capable.

Ex: common law murder – killing of another human being with malice aforethought.

– killing – actus reus

– another – actus reus

– human being – actus reus

– malice aforethought – mens rea

What is voluntary and what is not?

People v. Decina – seizure caused car to jump sidewalk. Seizure is not voluntary, but driving is and he knew he was prone to seizures. So is he liable?

Jones – Jones was convicted of involuntary manslaughter (negligent in taking care of Shirley Green’s kids) on an omission theory. Appealed. Remanded to find whether there was duty. Court says no omission liability unless there is a legal duty to act.

POSSESSION CRIMES – Possession of contraband (typical contraband: drugs, firearms, stolen goods)

To be guilty of possession of contraband, the defendant must have been aware that he/she had control over it (thus, if contraband is planted on someone, that person is not guilty of possession unless the person realizes he/she has control and decides to keep it)

Theories to prove possession: Actual vs. Constructive possession (You don’t get convicted on actual or constructive possession, prosecutor just uses it to prove general possession)

Actual possession = the contraband is found on the person’s body (incl. containers, bags, backpacks as long as the person was actually carrying them)

Note: Whether a defendant had actual possession seldom poses a difficult issue – pretty cut and dry

Constructive possession = the person was not physically carrying the contraband, but had sufficient access to and control over the contraband. An appreciable ability to control the destiny of that contraband (e.g., a safe-deposit box in a bank, or under the person’s bed)

Wheeler and Ireland: an “appreciable” amount of control over contraband is sufficient for possession, even if the control is shared with someone else

STATUS CRIMES – Cannot punish someone for status crimes. There has to be a voluntary act.


Mens rea = “mental culpability” or fault. Mental blameworthiness. Bad or evil state of mind

Must look at a statute and ask what mental culpability does this statute require to authorize a conviction. Some statutes require none (strict liability-usually traffic violations). But for serious crimes, mens rea is usually required
Requires temporal concurrence of mens rea and actus reus – The mental culpability required has to have been there at the time the person engaged in the conduct.

Model Penal Code § 2.02: types of mens rea

Purpose – accused has his conscious object of killing the victim. He was trying to achieve that result.
Knowledge – awareness or practical certainty that something will happen.
Recklessness – conscious disregard of substantial and unjustifiable risk. Thought about it, but disregarded it.
Negligence – defendant should have recognized substantial and unjustifiable risk. You didn’t think about it, but you should have thought about it.

Differences between:

purpose and knowledge: purpose denotes a desire to have the harm occur; knowledge denotes a complete callousness to whether the harm occurs or not

and recklessness: difference in degree only – knowledge requires awareness of extremely high likelihood that harm will occur; recklessness only requires recognition of moderately high likelihood that harm will occur
recklessness and negligence: difference in kind, not degree – recklessness requires subjective awareness of the likelihood of harm; negligence is satisfied if the accused SHOULD have been aware of the likelihood of harm, but did not think of it

Arranged in a perfect hierarchy from most wicked to least à if the accused is found to satisfy one term, he also necessarily satisfies all terms below it. (with some crimes like theft, it doesn’t work because there is no negligent theft)

Elonis v. U.S. – Distinguishing an objective standard from a subjective standard

State v. Peery – Distinguishing purpose from lesser states of mental culpability. In order to convict for indecent exposure, defendant had to be more than negligent or reckless – he must have had the purpose to be lewd (i.e., a desire for sexual gratification)

Villegas – Hep B blood vial case. “Knowingly places others in imminent danger of death or serious bodily injury”

Mens rea requirement = knowledge. “knowingly”

It is not just knowing that Hep B is dangerous and that it was in vials and that he was not properly disposing of vials. He has to have known that he was placing others in imminent danger of death or serious bodily injury.

Knowledge is satisfied by high probability/practicable certainty

MISTAKE OF FACT = lack of mens rea. (for exam: no separate mistake of fact doctrine. Either you had required mens rea or you don’t)

In CA: Mistake of fact is only a defense if you are charged with a specific intent crime. If you are charged with general intent, mistake of fact is not a defense.

Specific intent: intent to kill murder, burglary, theft, receiving stolen goods, conspiracy to do anything. Any attempt to do anything. Or crime with the intent to do something.
General intent: felony murder, involuntary manslaughter, forcible rape, statutory rape, sex offenses against children. Simple assault. Any strict liability offense is generally a general intent offense.

Cant really look at statute and figure out whether it is specific or general. Have to look at case law.

Problem with specific and general intent is it doesn’t map neatly into the ladder of mens rea, but usually (not always) specific intent crimes will contain some element of purpose or knowledge and usually general intent will be negligence or strict liability. Don’t know where recklessness falls.


Mens rea type claims of mistake (MENS REA) – Ultimate question is did this person have the mental culpability to convict this person of the offense. I made a mistake about the law and because of this, I didn’t have the mens rea necessary to be guilty under the statute that you are charging me with

Analysis: given this person’s mistake of law, is it tre that they lacked the mens rea under this statute? If yes, then not guilty.

Reliance type claims of mistake (ESTOPPEL) – Although I’m technically guilty

We had no way of getting it to you, no contact info, so we just put it on the internet somewhere and hoped that you stumble upon it at some point.


If the intoxication prevented you from forming whatever mental culpability is necessary for the charged offense, then it is a defense.

But voluntary intoxication is never a defense to a crime that only requires recklessness or negligence because you’re being reckless to commit the reckless crime. There is some responsibility in getting that drunk to commit a crime.

US v. Williams

Williams charged with 1) taking by intimidation. 2) bank robbery. (robbery is theft by force or threat of force)

The first on is general, so no intoxication defense. 2nd one is specific, so maybe.
Court believes D took alcohol and drugs to be under influence, but he was not so intoxicated that he didn’t know what he was doing and didn’t have the intent to rob the bank.
Takeaway à have to show that intoxication prevented you from forming mental culpability to commit the charged offense. (you don’t have to have the mental acuity to steal). It is extremely difficult to win on claim of intoxication even if it is theoretically available as a defense.

People v. Witfield – evidence of intoxication is allowed to negate malice necesaary for depraved heart murder on the grounds that murder is a specific intent crime for purposes of the intoxication defense.


When crime is committed by qualified agents of a corporation, both the corporation and/or those agents can be punished.

Majority rule also allows punishment of partnerships and partners

When are crimes of corporate personnel imputable to the corporation?

Federal approach: respondeat superior à removes the requirement of a P’s lawyer to show individual wrongdoing on the part of higher ups. Applies when

Actor is acting within scope of his/her authority and not in “frolic and detour”
Actor has to be acting on behalf of entity.
Acting for purpose of benefiting entity.

*If these 3 things are satisfied, then the corporation is automatically responsible and imputable. Once satisfied, there is not inquiry into whether there is wrongdoing by higher ups.

MPC approach (more restrictive). Limits corporate liability to cases where:

Statute giving rise to the indictable offense has a clear legislative purpose to make corporations themselves liable or
Statute imposes an affirmative duty on corporation to perform acts and the corporation fails to act or
Offense was authorized or recklessly tolerated by the board of directors or a corporate officer.

*essentially, there has to be wrongdoing by higher ups.