Master Deputy Jillian Olson, 29, died Thursday during an underwater training session on Lake Murray, the Lexington County Sheriff’s Department announced. Olson, a member of the department’s dive team since 2024, had accumulated over 100 hours of underwater experience, according to officials.
The Lexington County Coroner’s Office is investigating to determine the cause and manner of her death. The South Carolina Department of Natural Resources’ Investigations Unit and Aquatics Investigation and Recovery (AIR) team led recovery efforts, with assistance from the South Carolina Law Enforcement Division.
Sheriff Jay Koon expressed gratitude to the public safety agencies that responded to aid in the recovery efforts. Olson joined the sheriff's department in 2021 and was promoted to master deputy in the warrants division in 2025. She was scheduled to receive a five-year honorable service award next month and had previously received the Sheriff’s Tactical Operations Support Award in 2023, along with the Outstanding Judicial Services Deputy of the Year award.
Olson, a native of Illinois, graduated from Western Illinois University in 2019 with a bachelor’s degree in law enforcement and justice administration. She also held a master’s degree in student personnel services. According to Pastor Frank Anderson of St. Michael Lutheran Church, who knew Olson and her family for decades, her deep Christian faith informed her passion for law enforcement and her desire to serve others.
Lake Murray, where the incident occurred, is a man-made reservoir constructed in the 1920s for hydroelectric power. It covers more than 48,000 acres and has depths reaching nearly 200 feet. Olson, who was to be laid to rest on Wednesday, frequently spent time on the lake for both work and recreation. Her family recently purchased a house on the lake, where she enjoyed kayaking, paddle boarding, and jet skiing in her free time, finding serenity in the quiet amidst her demanding career, Anderson said. The deputy’s decision to join the dive team was described by Sheriff Koon as an example of her going “above and beyond.”