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Mark R. Thiessen

Fighting for the People and Winning.

733 E. 12th 1/2 Street
Houston, TX 77008

Phone: 713-864-9000

Website: thetexastrialattorney.com

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About Mark R. Thiessen

Mark Thiessen is a criminal trial lawyer and the Chairman/CEO of the Thiessen Law Firm in Houston, Texas. Mark is Board Certified in (1) Criminal Law by the Texas Board of Legal Specialization 2018; (2) DUI Law by the DUI Defense Lawyers Association 2018; and (3) DUI Defense Law by the National College for DUI Defense through the American Bar Association 2020. Mark earned the American Chemical Society-Chemistry and the Law (ACS-CHAL) Forensic Lawyer-Scientist designation, which is the highest form of scientific recognition available for lawyers. Mark is a frequent legal seminar lecturer, author of numerous published legal articles, and a faculty member for various organizations. Mark is the current DWI Committee co-chair and on the Board of Directors for Texas Criminal Defense Lawyers Association (TCDLA), 2020-21 President of Harris County Criminal Lawyers Association (HCCLA) and a Charter Member and Parlimentarian for DUI Defense Lawyers Association (DUIDLA). Mark is a 9 time Texas Super Lawyer and in the Top 100 Super Lawyers in Houston (2017-21). From 2019-21, Mark was the only DWI lawyer to be named to the Top 100 Super Lawyers in all of Texas. Mark has won DWI trials from total refusals up to quadruple intoxication manslaughter.

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FROM OUR BLOG

Ethics Task Force Blog

04/15/2025

Written by Jonathan Dichter The Heart of Client Care: Moving Beyond Case Management In the legal profession, we often talk about "case management" - the systems and processes that keep our cases moving efficiently. But what about *client care*? True client care goes beyond deadlines and filings; it's about treating clients as *people*-scared, uncertain, and in need of guidance. And when done...

Personal Contact: Using the Officer's Observations Against Them

03/10/2025

Written by Charles GoodwinEdited by Michelle Behan and Steven Hernandez The typical DUI investigation has three phases. It begins with the vehicle in motion and focuses on driving patterns that officers are trained might indicate impairment. Next is personal contact, where the officer will observe physical manifestations that are also purportedly correlated with alcohol ingestion and impairment. Finally, the officer will...

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