Attorneys
Locally Owned Since 1996
Free Initial Consultation
Over 24 Years of Experience
Rhonda Lockwood
Rhonda Lockwood is the owner of Lockwood & Zahrbock Kool Law Office in Sioux Falls, SD — a practice she proudly built from the ground up in 1996 and has led for over 30 years.
Before law, Rhonda earned her degree from SDSU and worked as a home-based therapist at Children’s Home Society, where she also became certified as a Level II alcohol and drug counselor. She went on to earn her law degree from the University of Tulsa in 1993, then honed her skills at the Minnehaha County Public Defender’s Office — before doing exactly what she always knew she would: opening her own firm.
Owning her own practice was never a question — it was simply the plan. Rhonda grew up watching her father run his own veterinary practice, and that shaped everything. Her family understood early on that you build your future on your own terms, and Rhonda has lived that truth every day since 1996.
Three decades later, she has never once doubted that decision.
Along the way, Rhonda met Tressa Zahrbock Kool and knew immediately she had found the perfect partner. Tressa matches her fierceness and loyalty — and together, they’ve built something Rhonda is deeply proud of.
Rhonda specializes in Family Law, an area she grew into and now champions with full conviction. She is direct, honest, and fiercely committed to her clients — even when the truth is hard to hear. Her philosophy is simple: “If you ‘own’ what is going on, the case will go smoother — but most importantly, your healing will start, and you can begin to discover what your next chapter is meant to be.”
Outside the office, Rhonda’s greatest pride is her family. She is fiercely devoted to her husband, their five boys, 3 daughter-in-laws, and is over the moon welcoming a new grandbaby into the fold. When she’s not in the courtroom, you’ll find her doing yoga, skiing, hiking, traveling, or cheering on her boys.
Lockwood & Zahrbock Kool Law Office is her baby. And she wouldn’t have it any other way.
Tressa Zahrbock Kool
As the co-owner of Lockwood & Zahrbock Kool Law Office (LZK), Tressa Zahrbock Kool believes that the strongest legal outcomes are built on a foundation of client education, empowerment, and deep collaboration. She has cultivated a highly collaborative culture where the client benefits from the collective intelligence, diverse strengths, and shared passion of a unified legal team. By building an educational and supportive environment where clients feel entirely secure sharing their true stories, Tressa and her talented legal team ensure that no client ever carries their legal burden alone. They invest the time to understand your journey—how you got here and where you want to go. Not everything has to be litigated. Tressa’s practice is built on empowering clients with options. Empowers you with non-litigation options to save your time, money, and emotional exhaustion, but the LZK team is always fully prepared and strategically positioned to litigate when aggressive advocacy is required.
Whether guiding clients through complex life transitions or streamlining amicable agreements, Tressa provides sophisticated legal solutions across a variety of practice areas.

Tressa’s passion for advocacy started early. She earned her Juris Doctor, Master of Public Administration, and dual bachelor’s degrees in Political Science and Criminal Justice, along with a minor in Business Administration. Before shifting to private practice, she spent two years gaining intensive courtroom experience at the Minnehaha County Public Defender’s Office.
Off the clock, Tressa fuels her physical and mental grit with long walks and heavy runs to fast bike rides and high-intensity yoga sculpt classes; she doesn’t stop moving. At home, she and her husband are learning to raise two teenage daughters.
Jill
Swanson
Meet Jill Swanson! Jill Swanson is an attorney at Lockwood & Zahrbock Kool Law Office.
Jill Swanson was born and raised in South Dakota, and she graduated Magna Cum Laude from the University of South Dakota with a Bachelor of Arts in History with a minor in Religious Studies. Jill attended the University of South Dakota Knudson School of Law following her undergraduate degree.
Throughout law school, Jill was a research assistant with the Archives and Special Collections in the I.D. Weeks' library and later the McKusick Law Library. She worked towards her Master's in History while attending law school.
Jill first worked at East River Legal Services for three years before joining the Lockwood & Zahrbock Kool Law Office team. Her work at East River Legal Services sparked a passion for family law and guiding individuals through stressful life moments with compassion and advocacy.
In her free time, Jill enjoys spending time with family and friends while working on her latest knitting project.
Robert Christenson
Bob graduated from the University of South Dakota with an undergraduate degree in Political Science, and after graduation, worked as a union carpenter in South Dakota and Colorado. After his carpentry work, Bob earned a graduate degree from the University of South Dakota in Public Administration.
After spending three years as Executive Director of the Voluntary Action Center in Sioux Falls, Bob pursued a law degree from the University. After law school, Bob worked in the Trust Department at Security National Bank in Sioux City, lowa.
In 1985, Bob started Christenson Law Office in Sioux Falls, specializing in Estate and Business planning.
Bob has been an active community volunteer, having served as Chairman of the committee that recommended to the City of Sioux Falls that the old Washington High School building be repurposed into the Washington Pavilion of Arts and Science, which
stands as a community landmark today.
Bob is the current President of the Badger Clark Foundation, a private not-for-profit organization promoting the arts in South Dakota through the poetry of Badger Clark, South Dakota's first Poet Laureate. Through his work with the Foundation, Bob was awarded the Certificate of Recognition by the South Dakota State Historical Society The Board of Trustees, for his contributions to South Dakota history.
Bob is licensed to practice before the United States Supreme Court and the 8th Circuit Court of Appeals, the South Dakota Federal District Court, the United States Tax Court, and the South Dakota Supreme Court.
Bob and his wife KrisAnne live in Sioux Falls and have four children, Brooks,
Jono, Kaitlin, and Maire Claire.
Of Counsel
Samantha Reuer
Meet Samantha Reuer! Samantha Reuer is an attorney at Lockwood & Zahrbock Kool Law Office.
Samantha was born and raised in Harrisburg, South Dakota. She graduated from Augustana University with a Bachelor of Arts in Psychology and a minor in Business. Following graduation, she began working at Avera Behavioral Health, where she spent more than four years serving individuals experiencing mental health challenges.
Samantha graduated from the University of South Dakota Knudson School of Law in May 2026, where she served as a Volume 70 Staff Writer and Volume 71 Associate Editor of the South Dakota Law Review. Her love of learning, problem-solving, and helping others led her to pursue a legal career.
While attending law school, Samantha continued working in the behavioral health field, where she gained valuable experience supporting individuals through challenging circumstances and developed strong skills in effective communication and thoughtful advocacy. These experiences ultimately led to her passion for family law.
In her free time, Samantha enjoys spending time with family and friends, reading, and spending time with her dog.
Monica
Mattson
Monica is a dedicated family law attorney who guides clients through some of life’s most personal and challenging legal matters with clarity, compassion, and strength. She understands that cases involving divorce, custody, support, and parenting time are never just legal disputes—they affect families, futures, and peace of mind. That is why she takes a client-centered approach, listening carefully, explaining each step of the process, and building strategies tailored to each family’s goals and circumstances.
After graduating from the University of North Dakota School of Law with honors, Monica returned to her home state of South Dakota. She began her legal career at East River Legal Services, where she learned that compassion for clients is just as important as knowledge of the law. After three years of serving the community at East River, Monica became a Minnehaha County Deputy State’s Attorney. She prosecuted juvenile and criminal matters, with a caseload primarily consisting of child abuse and neglect cases. While prosecuting child abuse and neglect cases, Monica knew helping children and families was a passion she wanted to focus on. After eight years as a prosecutor, Monica started working in private practice as a family law attorney.
Known for being both compassionate and tough, Monica is a steady advocate at the negotiating table and a strong presence in the courtroom. She works to resolve disputes efficiently when possible, but she is fully prepared to litigate when her clients’ rights, children, or financial security are at stake. Clients value her honesty, responsiveness, and determination to protect what matters most. With a practical mindset and a deep commitment to advocacy, Monica helps individuals move forward with confidence during difficult transitions.
Whether advocating for a negotiated resolution or preparing for trial, she remains focused on achieving thoughtful, strong, and lasting outcomes for every client she serves.
Outside the office, Monica treasures time with her daughter and other family members. When she is not with her family, you can find her on the back of her horse, Short Go Sharona.
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