Recognized as a Great Plains Super Lawyer by Thompson Reuters and a Top Attorney by Avvo (10/10), Colin Murphy is a criminal defense trial lawyer who has tried dozens of misdemeanor and felony cases to a jury over the last decade with numerous acquittals. He has also obtained dismissals of more than 130 other drug and OWI charges, including driver’s license revocations, through successful pre-trial rulings during the same period.

Colin focuses primarily on defending those accused of possessing, delivering, cultivating or manufacturing marijuana and other narcotics. He also helps individuals recover property that has been unlawfully seized through civil forfeiture, which allows Iowa law enforcement agencies to profit from large amounts of cash, firearms, vehicles and other property taken from innocent persons.

Colin also represents those charged with alcohol and drug-impaired offenses, ranging from public intoxication to OWI to vehicular homicide. He is twice published in the area of OWI defense. In 2014, he co-authored the first edition one of the few practice-specific treatises in the state, Iowa OWI Defense: The Law and Practice, published by Lawyers & Judges Publishing Company. He also wrote a chapter focusing on the use of independent forensic investigations, including crash data and blood alcohol analysis, in Defending DUI Vehicular Homicide Cases, 2013 ed. by Aspatore Books.

Colin takes a keen interest in developing and litigating issues in traffic stops and other search and seizure contexts to expand the rights of the accused. Most recently, his efforts to overturn a search warrant based on information gathered during warrantless nighttime trash rips led to a landmark Iowa Supreme Court decision in State v. Wright, 961 N.W.2d 396 (Iowa 2021).  The decision was the first to recognize the rejuvenated trespass doctrine in Iowa and find an expectation of privacy in garbage.  In doing so, the Iowa Supreme Court overturned a police tactic responsible for untold numbers of convictions during the past four decades.

Colin has since worked diligently to expand the scope of the trespass doctrine to K9 searches, the deployment of recording devices by confidential informants under the one-party consent rule in Iowa and other areas that have typically been analyzed under an expectation of privacy approach.

As trial counsel in State v. Pals, 805 N.W.2d 767 (Iowa 2011), he challenged the voluntariness of a detained driver’s consent to search his vehicle under the Iowa Constitution. The Pals decision is now one of the seminal cases on the issue of warrantless consent searches.

Colin’s knack for understanding and simply explaining complex scientific concepts such as infrared spectrophotometry in breath testing, headspace gas chromatography with flame ionization detection in blood and urine testing, statistical analysis and measurement uncertainty is well known throughout the Iowa state criminal defense bar. The same can be said for his work in exposing drug K9 “alerts” that were either false positives or otherwise cued by the handler. He is one of a few attorneys in the state who have successfully challenged a vehicle search based on these highly questionable “alerts.”

As an appellate lawyer, Colin has briefed and argued issues of constitutional and statutory importance before the Iowa Supreme Court and Iowa Court of Appeals. In 2012, he won Mitchell County v. Zimmerman, 810 N.W.2d 1 (Iowa 2012), in which a unanimous Iowa Supreme Court struck down a local road-protection ordinance as unconstitutional under the Free Exercise Clause of the First Amendment.

Over the past three years, his cannabis law practice has grown to include counseling Iowa growers and businesses by providing legal planning, regulatory support, corporate guidance and compliance strategies to help navigate the rapidly evolving hemp and CBD space.

Another practice area that continues to grow is the protection of the right to acquire, possess and carry firearms in Iowa.  Colin is a member of the USCCA, the premier concealed carry association in the United States, and a strong advocate for the fundamental right to self defense and defense of others.   He is also a member of the Iowa Critical Response Team that assists and counsels those involved in the exercise of self-defense with firearms.

Colin serves as the Executive Director of Iowa NORML.




NORML Legal Committee, 2011 – Present

National Cannabis Bar Association, 2018 – Present

National College of DUI Defense, 2008 – 2014

Iowa State Court Administration, District 2A Juduical Nominating Commission, 2014

Iowa Association for Justice, Board of Governors, 2009 – 2010

Iowa Association for Justice, Legislative Committee, 2008 – 2012

Iowa Association for Justice, Criminal Law Core Group, 2008-2012

Iowa State Bar Association, Criminal Law Section, Executive Committee, 2005-2008


Drake Law School, J.D. with Honors, 1996.
-Research Editor and Member, Drake Law Review.
-Member, Blackstone Inn of Court.
-Legal Intern, Federal Public Defender for the Southern District of Iowa.

Grinnell College, B.A. General Science-Biology, 1991.


Iowa OWI Defense: The Law and Practice, Lawyers & Judges Publishing Company, 2014.

Causation in Vehicular Homicide, Defending DUI Vehicluar Homicide Cases, Aspatore Books, 2013.

Asleep at the Wheel – 25 Ways to Lose Winnable DUI Cases, 2013.


Pharmacology of ETOH, Marijuana & Benzodiazapines, Certificate of Competency, Harrisburg, PA, 2011.

NHTSA Standardized Field Sobriety Testing, Practitioner Certificate of Completion, Denver, CO, 2009.

NPAS, BAC DataMaster and Basic Science of Evidential Breath Alcohol Testing, Certificate of Competency, Mansfield, OH, 2008.

Forensic Blood and Urine Testing, Certificate, Atlanta, GA, 2008.


Litigating the Intoxication Defense, IWCAC Symposium 2019

Unreasonable Sniff and Seizure, Iowa Association for Justice, Criminal Law Seminar 2013.

Curbing the “Infallible” Drug Dog, Iowa State Public Defender, Criminal Law Seminar 2011.

Forensic Blood Testing in OWI Cases, Iowa Association for Justice, Criminal Law Seminar 2010.

Understanding Standardized Field Sobriety Tests, Iowa Association for Justice, Annual Meeting 2009.

Recurring Suppression Issues in Drug Cases, Iowa State Bar Association, 2007.

in the news




Drug Charges . Distribution . Drugs in Vehicles – Interdiction . Possession . Minor in Possession of Alcohol . Misdemeanor vs. Felony . OWI . Public Intoxication . Vehicular Homicide/Serious Injury . Entrapment . Exclusion of Evidence . Intoxication . Justification . Expungement . Just Arrested . Know Your Rights . Attorney . Miranda . Search and Seizure . Speedy Indictment/Speedy Trial . Blog . Drunk Driving Defense . Boating While Intoxicated . Driving and Drugs . DUI Rights . Blood, Breath and Urine Testing . Exclusion of Evidence . Field Sobriety Tests . Preliminary Breath Test . Search and Seizure . OWI 1st, 2nd and 3rd . Drunk Driving – Anatomy of an Investigation . OWI – Drunk Driving Basics . Underage OWI . Boating While Intoxicated . Collateral Consequences . OWI 1st . OWI 2nd . OWI 3rd . Serious Injury by Vehicle . Vehicular Homicide . Iowa Drivers Rights Card . Vehicular Homicide/Serious Injury by Vehicle . How Committed . Representative Vehicular Homicide Cases . Specialized Defense