Arrested or Charged with Murder in the First Degree (RSMo § 565.020) in Missouri?

October 15, 2025

If someone has been arrested or charged with Murder in the First Degree in Missouri, they’re facing the most serious criminal charge in the state. The consequences are life-altering, with potential punishments ranging from life imprisonment without the possibility of parole to the death penalty. At Rose Legal Services, we understand the gravity of these charges and are passionate about helping good people get a second chance.

What is Murder in the First Degree in Missouri?

Under Missouri Revised Statute § 565.020, “A person commits the offense of murder in the first degree if he or she knowingly causes the death of another person after deliberation upon the matter.”

The key elements that distinguish Murder in the First Degree from other homicide charges are:

  • Knowingly causing death – The person must have been aware their actions would cause death
  • Deliberation – The person must have considered and thought about taking another’s life before acting

This deliberation requirement is what separates first-degree murder from second-degree murder and other forms of homicide. Deliberation doesn’t require extensive planning over days or weeks – it can occur in a matter of moments. However, the prosecution must prove beyond a reasonable doubt that the defendant consciously considered causing death and made the decision to do so.

Penalties for Murder in the First Degree

Murder in the First Degree is classified as a Class A felony in Missouri, but the penalties go far beyond typical Class A felony sentences. According to RSMo § 565.020:

For adults 18 years or older at the time of the offense:

  • Death penalty, or
  • Life imprisonment without eligibility for probation, parole, or release (except by act of the governor)

For persons under 18 years at the time of the offense:

There is no middle ground with these penalties – a conviction means either execution or spending the rest of one’s natural life in prison. Missouri remains one of 27 states that maintains capital punishment as a sentencing option for first-degree murder.

Aggravating Circumstances That Can Lead to Death Penalty

When the death penalty is being considered, Missouri law requires the judge or jury to consider specific aggravating circumstances listed in RSMo § 565.032. These circumstances can make the difference between life imprisonment and execution. The 17 statutory aggravating circumstances include:

  • Prior murder conviction or serious assaultive criminal convictions
  • Multiple homicides – committing murder while engaged in another unlawful homicide
  • Creating great risk of death to multiple people through weapons or devices
  • Murder for hire or financial gain
  • Killing law enforcement, prosecutors, or judicial officers during or because of their official duties
  • Contract killing – causing, directing, or being hired to commit murder
  • Particularly heinous crimes involving torture or depravity of mind
  • Killing peace officers or firefighters performing official duties
  • Murder by escaped prisoners or those in lawful custody
  • Avoiding arrest – killing to prevent lawful arrest or custody
  • Murder during serious felonies like rape, sodomy, burglary, robbery, kidnapping, or drug crimes
  • Killing witnesses in investigations or prosecutions
  • Killing corrections employees or inmates
  • Murder during hijacking of planes, trains, ships, buses, or other public transportation
  • Concealing drug crimes – murder to hide felony drug offenses
  • Preventing drug prosecutions – killing to stop someone from aiding prosecution
  • Gang-related murders during criminal street gang activities

The prosecution must prove at least one aggravating circumstance beyond a reasonable doubt for the death penalty to be considered.

Mitigating Circumstances That May Reduce Punishment

Missouri law also recognizes seven statutory mitigating circumstances that the defense can present to argue against the death penalty:

  • No significant criminal history – The defendant has little or no prior criminal activity
  • Extreme mental or emotional disturbance at the time of the murder
  • Victim participation or consent in the conduct leading to death
  • Minor role as accomplice with relatively minor participation
  • Extreme duress or domination by another person
  • Substantially impaired capacity to appreciate criminality or conform to law
  • Young age of the defendant at the time of the offense

These mitigating factors don’t excuse the crime, but they can persuade a judge or jury to impose life imprisonment rather than death.

Building a Defense Against First-Degree Murder Charges

When someone faces Murder in the First Degree charges, several defense strategies may be available:

Challenging the Elements

The prosecution must prove both that the defendant knowingly caused death AND that they deliberated beforehand. If either element cannot be proven beyond a reasonable doubt, the charge may be reduced to a lesser offense.

Self-Defense or Defense of Others

Missouri recognizes the right to use deadly force when reasonably necessary to protect oneself or others from death or serious physical injury.

Mental State Defenses

Severe mental illness, intoxication, or emotional disturbance may negate the deliberation element or provide grounds for mitigation.

Mistaken Identity or False Accusations

DNA evidence, alibi witnesses, and thorough investigation can expose cases of wrongful identification.

Constitutional Violations

If law enforcement violated constitutional rights during the investigation, key evidence might be suppressed, weakening the prosecution’s case.

The Importance of Experienced Legal Representation

Murder in the First Degree cases require attorneys with extensive experience in capital litigation. At Rose Legal Services, our team of multiple attorneys dedicates our practice exclusively to criminal defense. We have the knowledge, resources, and dedication necessary to handle these complex cases.

Our approach includes:

  • Thorough investigation of all evidence and circumstances
  • Strategic defense planning tailored to each case’s unique facts
  • Negotiation with prosecutors when appropriate to seek reduced charges
  • Trial advocacy when cases proceed to trial
  • Mitigation development to present compelling reasons against death sentences

We believe that a criminal defense requires full-time focus and attention, which is why we limit our practice exclusively to this area.. Unlike many lawyers who take criminal cases, we will never be distracted by personal injury cases, bankruptcies, divorce cases, or anything else.

What to Do If You’re Charged with Murder in the First Degree

If you have been arrested or charged with Murder in the First Degree:

  • Exercise the right to remain silent – Don’t discuss the case with anyone except an attorney
  • Contact an experienced criminal defense attorney immediately
  • Preserve any potential evidence that could support the defense
  • Document everything about the incident and investigation
  • Follow your attorney’s advice regarding all aspects of the case

Time is critical in murder cases. Evidence can disappear, witnesses’ memories fade, and early decisions can have lasting consequences.

Contact Rose Legal Services Today

At Rose Legal Services, we have helped thousands of people who have been charged, arrested, or investigated for crimes. We are passionate about helping good people get a second chance.

We pride ourselves on excellent client service and communication. Our team will work together for the best outcome possible.

If someone is facing Murder in the First Degree charges in Missouri, don’t wait. Contact us today to schedule a free and confidential consultation.

Your defense starts with a conversation.

Author Bio

Scott Rose

Scott Rose, an experienced criminal defense lawyer and founder of Rose Legal Services, has been practicing law for over 25 years. He is dedicated to representing clients facing criminal charges and providing legal representation on various cases, including DWI, misdemeanor, and felony cases.

After graduating from the University of Virginia School of Law, he gained valuable experience working for a United States Senator and as a Judicial Law Clerk for the Chief Judge of a United States District Court. Throughout his legal career, W. Scott Rose has committed to providing high-quality legal representation to his clients, earning him a spot in the National Top 100 Trial Lawyers.

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