Missouri's state auditor, Tom Schweich, a Republican candidate for governor, died on Thursday, Governor Jay Nixon said in a statement.
Schweich, 54, had been reelected in November.
The St. Louis Post-Dispatch reported, citing an unnamed police source, that Schweich had sustained a self-inflicted gunshot wound at his home. This report could not be confirmed immediately.
Schweich was "a brilliant, devoted and accomplished public servant who dedicated his career to making Missouri and the world a better place," Nixon said in a statement.
Nixon ordered flags lowered to half-staff in honor of Schweich.
(Reporting by Kevin Murphy in Kansas City, Missouri; Editing by Eric Beech)
Watch a report on Schweich's death, as aired on WTVI-TV on Thursday, below.