(CNN) A deputy with the Cowlitz County Sheriff's Office in Washington was fatally shot Saturday night, a death Sheriff Brad Thurman said was the agency's first in the line of duty in its 165-year history.

Justin DeRosier, 29, was responding to a disabled vehicle when he reported to other deputies that he had been shot, Thurman said during a press conference on Sunday.

DeRosier was flown to PeaceHealth Southwest Medical Center in Vancouver, where he died, Thurman said.

DeRosier leaves behind a wife and a 6-month-old daughter, Thurman said while holding back tears.

Thurman said DeRosier had been with the department since May 2016 as a patrol deputy and boat operator. DeRosier would have started training to be a narcotics investigator with the drug task force in July.

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