Helping Idahoans Move Forward After Injury
For more than 120 years combined, the attorneys at Petersen, Parkinson & Arnold have helped injured workers, accident victims, and individuals seeking disability benefits navigate some of life’s most difficult challenges.
We believe legal guidance should be straightforward, accessible, and focused on results. Whether you’re dealing with a workplace injury, a denied disability claim, or the aftermath of a serious accident, our team is here to help you understand your options.
James Arnold
Workers’ Comp & Personal Injury | Se Habla Español
James Arnold’s commitment to injured workers began long before he became an attorney.
Growing up on a family farm, he worked alongside laborers whose physically demanding jobs often went unnoticed. Those experiences gave him a firsthand understanding of the challenges many workers face and shaped the way he approaches his legal practice today.
James focuses on workers’ compensation and personal injury cases throughout Idaho. He has argued multiple cases before the Idaho Supreme Court, including a landmark workers’ compensation case that helped secure permanent disability benefits for undocumented workers injured on the job.
Known for his practical approach and dedication to his clients, James works to ensure injured workers understand their rights and have access to the benefits they deserve.
Memberships: Idaho Trial Lawyers Association
Certifications: Idaho Workers’ Compensation Specialist (Idaho Trial Lawyers Association)
Matthew Vook
Workers’ Comp & Personal Injury
Matthew Vook brings a unique perspective to workers’ compensation law because he’s worked on nearly every side of the process.
After serving in the U.S. Navy and earning his law degree, Matthew began his legal career with the Idaho Industrial Commission, the state agency responsible for administering workers’ compensation claims. He later represented insurance companies in workers’ compensation defense cases before transitioning to represent injured workers.
Today, Matthew uses that experience to help clients navigate the complexities of the workers’ compensation system with confidence. Having seen how claims are evaluated from multiple perspectives, he understands the challenges injured workers face and works diligently to help them pursue the benefits they deserve.
Matthew believes in providing honest guidance, clear communication, and practical solutions so clients can make informed decisions about their cases and their future.
Certifications: Idaho Workers’ Compensation Specialist (Idaho Trial Lawyers Association)
Trenton Arnold
Workers’ Comp & Personal Injury
Trenton Arnold’s legal career began at Petersen, Parkinson & Arnold long before he became an attorney.
He joined the firm in 2021 as a legal assistant, working full-time while attending classes at night and on weekends to earn his Bachelor of Science in Applied Business Management from BYU-Idaho. He went on to earn his Juris Doctor from the University of Idaho in 2024 before passing the Idaho Bar Exam and joining the Idaho State Bar as a practicing attorney in 2025.
Trenton focuses on workers’ compensation and personal injury cases throughout Idaho. His experience working closely with injured clients has given him a firsthand understanding of the challenges they face, as well as the confusion that often comes with navigating Idaho’s legal system and understanding the benefits available to them.
Known for his thoughtful approach and dedication to client advocacy, Trenton is passionate about educating clients, guiding them through every step of the legal process, and helping them pursue the full benefits and compensation they deserve.
Brad Parkinson (of Counsel)
Social Security Disability
Brad Parkinson believes that one of the most important parts of practicing law is helping people navigate challenging situations with confidence.
What first drew him to the legal profession was the opportunity to solve problems and guide people through complex processes during some of the most stressful times in their lives. Over the years, that commitment has remained at the center of his practice.
Brad understands that many people feel intimidated by the legal system. That’s why he focuses on creating an environment where clients feel comfortable asking questions, sharing concerns, and understanding their options. He believes effective legal representation starts with listening, building trust, and helping clients feel supported every step of the way.
Whether assisting clients with personal injury, disability, or other legal matters, Brad is committed to providing clear guidance and practical solutions tailored to each individual’s situation.
Affiliations: Of Counsel – Olinsky Law Group, Sustaining Member of National Organization of Social Security Claimants’ Representatives, Admitted to Ninth Circuit Court of Appeals
Mike McBride (of Counsel)
Workers' Comp & Personal Injury
Mike McBride is Idaho’s only certified specialist in both personal injury and workers’ compensation practices. This designation required intensive specialized training as well a significant amount of practice in both the courtroom and in Industrial Commission hearings. Thus, he is uniquely qualified to assess and secure benefits and compensation for injured on-the-job workers and non-work-related injuries, such as those sustained in car accidents and defective products.
Mr. McBride graduated from Brigham Young University in 1980 and obtained his Juris Doctorate degree at the University of Idaho in 1982. After law school, he served as a prosecuting attorney in Caldwell, Idaho from 1983–1984, trying criminal cases before juries in Canyon County. In 1984, he returned to Idaho Falls and established his injury claim practice.
His trial work has resulted in a $3 million verdict relating to defective farm equipment in federal district court and multiple trial verdicts exceeding $100,000.00. He brings this experience and insight to injured clients at Petersen, Parkinson & Arnold.
Certifications: Certified Workers’ Compensation Specialist (Idaho Trial Lawyers Association), Certified Personal Injury Specialist (Idaho Trial Lawyers Association)
Josie Fajardo
Senior Legal Assistant | Se Habla Español
Josie has been with Petersen, Parkinson & Arnold since 2008, specializing in workers’ compensation. She prepares legal documents, manages case communications, and helps keep matters moving for clients and attorneys. Known for her attention to detail and client service, she helps clients feel informed and supported. Outside the office, she enjoys reading, cooking, hiking, camping, traveling, and exploring Idaho’s parks.
Marcy Martinez
Legal Assistant
Marcy has been part of the Petersen, Parkinson & Arnold team for more than 15 years. She works closely with Brad Parkinson, assisting Social Security Disability clients through every stage of the claims process, including applications and appeals.
Marcy enjoys helping people navigate complex
situations and obtain the benefits they need. Her experience, compassion, and dedication make her a valued member of the PPA team.
Tracy Belton
Legal Assistant
Certifications: Idaho Workers’ Compensation Specialist (Idaho Industrial Commission)
Tracy is a Certified Idaho Workers’ Compensation Specialist with more than 25 years of experience helping injured workers navigate the claims process. She works closely with attorney Matthew Vook and is dedicated to supporting clients throughout their workers’ compensation cases.
Outside of the office, Tracy enjoys taking walks along the river and spending time outdoors.
Katelyn Martinez
Legal Assistant
Certifications: Idaho Workers’ Compensation Specialist (Idaho Industrial Commission)
Katelyn is an Idaho Workers’ Compensation Specialist certified by the Idaho Industrial Commission. Since joining Petersen, Parkinson & Arnold in 2019, she has worked closely with attorney James C. Arnold, helping injured workers navigate the workers’ compensation process.
Katelyn enjoys being part of a team that is dedicated to helping clients understand their rights and pursue the benefits they deserve.
Collette Lott
Legal Assistant
Collette has more than 25 years of experience in legal and administrative support and has been a member of the Petersen, Parkinson & Arnold team for over seven years.
As a lifelong Idaho Falls resident, she enjoys working closely with clients and helping them navigate difficult situations. Collette takes pride in providing support and making a positive difference during challenging times.
Stacey Knueppel
Paralegal
Stacey has more than 40 years of paralegal experience, including 30 years in San Diego working on complex litigation and class action cases. Her background includes high-profile matters involving personal injury, product liability, and mass tort claims.
With extensive experience in plaintiff personal injury law, Stacey brings a wealth of knowledge and insight to the clients and attorneys she supports.
Kollinda Vollmer
Bookkeeper
Kollinda serves as the firm’s Bookkeeper, bringing a strong background in business management, finance, and 16 years of banking experience. She enjoys being part of a team dedicated to helping clients through challenging times.
Outside of work, Kollinda enjoys spending time with her family, cheering on her children at sporting events, and getting lost in a good book.
Maida Damian
Legal Assistant | Se Habla Español
Maida has worked as a legal assistant since 2017 and is part of the Petersen, Parkinson & Arnold team in the Twin Falls office. She works closely with attorney Matthew Vook, helping injured workers navigate their workers’ compensation claims.
Maida enjoys being part of a team that puts clients first and is committed to helping people through challenging situations. Outside of work, she enjoys spending time with her family, reading, hiking, and enjoying the outdoors.
Lisa Kidman
Legal Assistant
Alicia Peterson
Receptionist
Alicia serves as the receptionist in our Idaho Falls office, helping create a welcoming experience for clients and visitors. She assists with day-to-day communications and helps connect clients with the information and support they need.