LEXINGTON, S.C. — Lexington County Sheriff’s Department Master Deputy Jillian Olson died July 30, 2026, during an underwater dive-team training session on Lake Murray, according to the department. She was 29.

The Sheriff’s Department announced Olson’s death the following morning. The agency said Olson joined the department in 2021, served first in patrol and later as a warrant deputy, and was promoted to master deputy in the Warrant Division in 2025. She had served on the dive team since 2024.

End of Watch

The department said the South Carolina Department of Natural Resources is leading the investigation, assisted by the South Carolina Law Enforcement Division. The Lexington County Coroner’s Office is conducting a separate investigation to determine the cause and manner of death.

WIS News 10 also reported that Olson died during dive-team training on Lake Murray, citing the Sheriff’s Department.

The circumstances remain under investigation. ThinBlueNews will not speculate beyond information released by the responsible agencies. As of the morning of Aug. 1, Olson had not yet appeared in ODMP’s public recent-officer feed; this memorial relies on the Sheriff’s Department’s official announcement and corroborating local coverage and will be updated if authoritative findings materially change the record.

End of Watch: July 30, 2026
Master Deputy Jillian Olson
Lexington County Sheriff’s Department — South Carolina
Age: 29
Department service: since 2021
Dive-team service: since 2024

Service recognized

Sheriff Jay Koon said Olson “exemplified commitment and service” and would be remembered for work she performed without fanfare. The department said the Lexington County Sheriff’s Foundation named her its outstanding judicial services deputy of the year after she created reference guides and document templates that improved deputy training and workflow.

Olson had also received the department’s tactical operations support award in 2023 and was scheduled to receive a five-year honorable service award in August, according to the agency. A native of Illinois, she earned bachelor’s and master’s degrees from Western Illinois University.

ThinBlueNews extends its deepest condolences to Master Deputy Olson’s family, friends, colleagues and the Lexington County community. May her service be remembered with gratitude, and may those closest to her be afforded privacy and support.

Sources and photo attribution

Photo: Official End of Watch memorial portrait for Master Deputy Jillian Olson, published by the Lexington County Sheriff’s Department with its July 31 announcement. Used for editorial identification and memorial reporting; no likeness was generated.

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