Thiessen Law Firm is a premier Houston-based legal practice specializing in aggressive DWI and criminal defense, renowned for its exceptional trial advocacy and scientific approach to complex cases. As one of the most distinguished firms in Texas, it stands out for having the only attorney in America triple board-certified in DWI defense, criminal law, and DUI law, combined with a relentless commitment to client-centered representation.
The firm employs a rigorous, evidence-based defense strategy, leveraging deep scientific knowledge of DWI testing procedures and forensic analysis to challenge prosecution evidence effectively. Led by Mark Thiessen, an ACS/CHAL Lawyer-Scientist and multiple-time Super Lawyer honoree, the team focuses on high-stakes criminal and DWI cases, representing individuals facing severe charges such as intoxication manslaughter, felony DWI, and drug crimes. They prioritize accessibility, offering 24/7 support and transparent communication throughout each case.
Services Offered
- DWI Defense (First Offense, Second Offense, Third Offense, Multiple Offenses, Felony DWI)
- Intoxication Assault
- Intoxication Manslaughter Defense
- DWI Blood Testing Challenges
- DWI Breath Test Defense
- License Suspension Hearings
- Drug DWI (Marijuana, Prescription Drugs, Cocaine, Heroin, Psychedelics)
- Underage DWI
- BWI (Boating While Intoxicated)
- Criminal Defense (Assault, Aggravated Assault, Domestic Violence, Drug Crimes, Homicide, Manslaughter, Murder, Capital Murder, Prostitution, Arson, Robbery, Burglary, Theft, Weapons Charges)
- Expunction & Non-Disclosure
- Reckless Driving Defense
- Vehicular Manslaughter Defense
- Public Intoxication Defense
- Personal Injury (Automobile Accidents, Truck Accidents, Motorcycle Accidents, Plant Explosions, Wrongful Death, Catastrophic Injury, Traumatic Brain Injury)
- Family Law (Custody Battles, Divorce, Fathers’ Rights, Child Support)
Serving clients across Texas, including Harris, Fort Bend, Galveston, and Montgomery Counties, the firm offers services in both English and Spanish. Notable achievements include successful defenses in high-profile intoxication manslaughter cases, dismissals of DWI charges with blood alcohol levels exceeding 0.15, and a consistent record of not guilty verdicts in complex criminal trials.
