Attorneys
Locally Owned Since 1996
Free Initial Consultation
Over 24 Years of Experience
Rhonda Lockwood
Meet Rhonda Lockwood, owner of Lockwood & Zahrbock Kool Law Office in Sioux Falls, SD. After graduating from SDSU, Rhonda worked as a home based therapist at Children’s Home Society in Sioux Falls. During her time with Children’s Home Society, she became certified as a Level II alcohol and drug counselor. Rhonda worked for Children’s Home Society for three years before attending law school at the University of Tulsa. She graduated in 1993, when she started to work for the Minnehaha County Public Defender’s Office. She worked with the public defender’s office for three years before starting her practice. She always knew she wanted to run her own business and that’s when, in 1996, she started Lockwood & Zahrbock Kool Law Office. Since practicing law starting in 1996, Rhonda has grown to specialize in Family Law. She wasn’t planning on working in this area, but she’s grown herself into enjoying this area of law. Rhonda is here to help you see the truth with what you’re involved in and figuring out a way to resolve your case as quickly as possible. Rhonda loves working for Lockwood & Zahrbock Kool Law Office because this is “her baby”. She never once has doubted herself and is proud of the practice she has started. Outside of work, Rhonda is passionate about her family and will always put them first. She enjoys watching her boys in sports, doing yoga, running, water and snow skiing, and spending time with her husband. Rhonda is going to work hard for you and be honest—even when you do not want to hear it. The reason is, Rhonda says, is “if you ‘own’ what is going on, the case will go smoother; but, most importantly, your healing will start and you can start to discover what your next chapter is meant to be!”
Tressa Zahrbock Kool
Meet Tressa Zahrbock Kool. Tressa is owner of Lockwood & Zahrbock Kool Law Office.
Tressa received her degree from the University of South Dakota where she graduated with a double major in political science and criminal justice and minor in business administration. After receiving her undergraduate degree, Tressa went to University of South Dakota Law School and graduated with her juris doctrine and masters in public administration. After graduation she worked for the Minnehaha County Public Defender’s Office for two years before starting in private practice.
Tressa’s main area of expertise is in custody and divorce cases. She strives to make Lockwood & Zahrbock Kool Law Office a compassionate office where her clients can feel comfortable sharing their life stories. Tressa is a strong advocate for her clients providing them confidence and security that Lockwood & Zahrbock Kool Law Office is handling their life situations. If there’s one situation that Tressa is passionate about solving it is a family’s parenting plan with their children and working with parents to come up with a “parenting plan”. Tressa will work with parents to determine a schedule on the basis of their family situation needs and desires.
In addition to family law, Tressa specializes in criminal law matters. Tressa and her team will take the time to understand a client’s case and their journey of how they got where they are now, and where they might be going.
Tressa enjoys working at Lockwood & Zahrbock Kool Law Office because of the fabulous talented team she gets to work with everyday. Everyone at Lockwood & Zahrbock Kool Law Office has a strong desire to be an advocate for the client. She lives in Sioux Falls with her husband and two young 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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