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AGGRESSIVE HOUSTON DWI LAWYERS

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Google 240+ 5 star rating, Avvo 230+ 99% rating Mark Thiessen
Company Awards: Super Lawyers, AV Preeminent Martindale-Hubbell Lawyer Rating, The National Trial Lawyers Top 100, Avvo Superb 10.0 Rating
Mark Thiessen

The only DWI Attorney Selected To:

Awards Top 100 HTX TX

In Any Case, in Every Court — We Fight for the People

Notable Houston DWI Victories

not guilty

Intoxication Manslaughter | State v. G.G.

Harris County 248th

8/30/24

While the Not Guilty verdict may have been in our client’s favor, there are truly no winners in Intoxicated Manslaughter cases. The jury was not happy to render a verdict of Not Guilty but, they followed the law and had doubts about intoxication. The jury took their oath very seriously and stayed true to their doubts, not letting their emotions overcome a just verdict. Thank you to that jury for giving our client his life back.

Our client was speeding and texting while driving. Unfortunately, he had a tragic accident killing another man by rear ending him at a stop light.  The blood test of .21 residual blood and .19 consent blood draw just didn’t add up.  Only 1 witness/police officer said he smelled alcohol on our client out of 15 witnesses. None of the witnesses said he had even slurred speech, which the hospital video confirmed. He never asked to use the restroom once. He was given fentanyl and had a head injury. He was confused and out of it, but not slurred or drunk. The blood just didn’t add up. Amanda Culbertson did a great job explaining the problems with lavender topped tubes, serum samples, and pulling cold blood. Don Egdorf helped the jury understand what a proper police investigation should have entailed and what voluntary consent should look like. The DAs were professional and tried a great case. At the end of the day, there was just too much doubt for intoxicated manslaughter.

Thank you also to the Judge for giving us time and patience to try a very difficult and emotional case. Thank you to my office for preparing this case, having everything in order, and holding down the fort while we were out for 2 weeks. Lastly, and most importantly, thanks to God for aligning all the stars and putting the right people in the right seats after 2,295 days. We sincerely hope that both families can find peace and closure after this tragic accident.

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Mark Thiessen

Mark Thiessen

Houston DWI & Criminal Law Specialist

“I’m a 3x Board Certified, trial-tested DWI Specialist focused on fighting for my client's freedom. If you hire our Houston DWI Law firm, we're available 24/7, because, at the end of the day, we work for you. As one of only three attorneys in all of Texas to be Board Certified in DWI Defense by NCDD and in Criminal Law by Texas Board of Legal Specialization, my clients can count on specialized, expert representation that most firms simply can’t deliver.”

What to expect?

Thiessen Law Firm. Well-known for both award winning Houston DWI Lawyers and aggressive trial-tested criminal defense techniques, we fight like no other, for your DWI case. Our trial attorneys not only fight for positive results, we also care deeply about the overall well-being of our clients.

Why Choose Thiessen Law Firm?

  • Proven Houston DWI Lawyer
  • Aggressive Criminal Defense Attorney
  • Board Certified in Criminal Law by Texas Board of Legal Specialization
  • Board Certified in DWI Defense Law by NCDD
  • ACS/CHAL Lawyer Scientist
  • The ONLY DWI lawyer to be selected to Top 100 Super Lawyers in Texas (2019-2023) and Houston (2017-2023)
  • Free DWI & Criminal Case Evaluation
  • No Hourly Rates
  • 24/7 Accessibility
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Houston DWI & trial lawyers that fight for you in Houston and all Texas counties

Our Houston DWI Attorneys always fight our hardest. We tell the truth about your DWI or DUI case, and facts take precedence over promises. We hold honesty and virtue in highest regard and it is the foundation of ensuring your DWI or criminal defense case ends with a satisfying, positive outcome.

When you get a Houston DWI, DUI or other criminal charge in Harris County, your life is changed, no matter the verdict. At Thiessen Law Firm, you will be represented by a Houston DWI lawyer who will ensure you’re able to continue on with the life you want. You’ll never feel forced into taking a deal that you don’t want, or accepting terms you don’t fully understand. Mark Thiessen isn’t just a top Houston DWI lawyer. He’s also recognized as an ACS CHAL Lawyer-Scientist for his efforts to understand the science and technology behind DWI testing. This investment in his education and training provides clients with the knowledge needed to fight for their rights effectively and fairly.

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Not Guilty Verdicts

Client Testimoanials

Speaking Engagements

Awards & Honors

Mark Thiessen's Publications

You’ve got 15 days to save your license. Choose a lawyer who can defend it.

Thiessen Law Firm is ready to protect your life.

At Thiessen Law Firm, we prioritize your peace of mind and fight to protect you from injustices. Here, you’re more than just a case number, and you don’t have to face the severity of the justice system alone. Contact us today to schedule an Administrative License Revocation hearing, save your license, and preserve your rights.

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Latest DWI & Criminal Defense News

Thiessen Law Firm

March 8, 2025 . 7 min read

Thiessen Law Firm

March 7, 2025 . 8 min read

Thiessen Law Firm

March 6, 2025 . 7 min read

People Are Reading

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In The Media

In The Media
www.lubbockonline.com

Jurors find woman not guilty of intoxication manslaughter in fatal West Lubbock crash

The defense attorney for a 23-year-old woman said a flawed Lubbock police crash investigation provided enough reasonable doubt for a 12-member jury to find his client not guilty in a fatal 2014 West Lubbock wreck.

Read the full story

Speaking Engagements

As an attorney selected as a Texas Super Lawyer, Mark Thiessen has consistently set high standards in his field since establishing his firm. His scientific investigation process & comprehensive list of victories has brought him to the forefront of national recognition as he is sought by industry leaders & legal organizations to deliver trial strategy seminars.

Houston, Texas

TCDLA Top Gun Advanced DWI CLE – Breaking Down Blood Testing for Lawyers

San Antonio, Texas

State Bar of Texas Advanced Criminal Law CLE – Cross Examining the SFSTs

Houston, Texas

Harris County Managed Assigned Counsel (MAC)/ SFSTs and the Disconnect Defense

Happy Clients

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Choosing a Houston DWI Lawyer

If you or a loved one are fighting a Houston DWI, it may be tempting to search for cheap DWI lawyers in Houston, TX. Don’t gamble with your freedom and reputation, even a DWI in Texas, first offense can be life-altering.

In fact, every DWI and criminal offense is serious: DPS surcharges, intoxication manslaughter, a BWI in Houston. Look beyond a DWI lawyer in Houston and their cost, you need a Houston DWI attorney who wins.

For example, many websites may claim to be the best DWI lawyer in Texas. But how many of those DWI attorneys have beat a quadruple intoxication manslaughter charge? Thiessen Law Firm has. In fact, our Houston DWI lawyers have beaten intoxication manslaughter charges, DWI blood tests, DWI breath tests, and have even seen successful outcomes where a client admitted to being drunk on video.

In addition to being a Super Lawyer and ACS-CHAL Lawyer Scientist, since July 14, 2022, DWI Specialist Mark Thiessen has been the only attorney in America who is Triple Board Certified in the following areas:

  • Criminal Law by the Texas Board of Legal Specialization - 12/31/2018
  • DUI Defense by the National College for DUI Defense as approved through the American Bar Association - 7/14/2022
  • DUI Law by the DUI Defense Lawyers Association - 4/26/2018
  • Board Certified Advocate in Criminal Trial Law by the NBTA Foundation - 8/27/2021
Mark is also rated a 10.0 Superb Avvo-rated lawyer with 99% client satisfaction.

Don’t worry about finding a “DWI lawyer near me”, Thiessen Law Firm fights DWI in Texas, all across the state. Need a DWI Lawyer in Galveston County? The team of Houston DWI attorneys at Thiessen are ready to fight for you.

Get a Houston DWI team with winning experience on your side, request a free consultation below.

Free DWI & Criminal Case Consultation

Call 713.864.9000 or fill out the form below for a free consultation.

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