Updated 11:16 a.m.

Incumbent Rob Cook will face challenger Wayne Thompson in a runoff election May 24 for the Republican nomination for the Fort Bend County Constable Precinct 3.

No Democrats ran for the position so the Republican winner will run unopposed in November.

With all 30 precincts reporting, Cook had 35 percent, or 6,134 votes. Thompson finished with 26 percent, or 4,587 votes. John Miller finished third with 22 percent of the vote—3,813 votes—while John Minchew tallied 17 percent of the vote, or 3,080 votes.

Cook—who has held the office since 1988—has only faced up to two challengers in previous elections. 

"I've never had a runoff, so I don't have any expectations," Cook said.

He said he plans to ramp up his campaign for the runoff.

"We're going to try to involve a lot more of the homeowners groups and try to get them involved getting the vote out," he said.

Thompson has worked in law enforcement for 14 years and served with the Texas National Guard and Texas State Guard. He ran for Precinct 3 Constable in 2012, but was eliminated from the ballot when a census redistricted the boundaries of the precinct.

"We feel very good," Thompson said. "It was a loud and clear message. Sixty-five percent of the people voted against [Cook]."

Miller, who retired from the the Houston Police Department after 31 years of service, is the assistant vice president of the Cinco Southwest Municipal Utility District No. 4.

Minchew formerly worked as a police chief in Florida and was also a city of Houston police officer. He runs a Houston security and investigation company.

Prior to becoming constable, Cook worked in law enforcement for seven years. He also worked in the oil and gas industry and was a junior high school science teacher.

He became the Precinct 3 constable after his predecessor was removed from office.

Fort Bend’s Constable Precinct 3 position comes with a four-year term and $98,435 in pay.

All results are unofficial until canvassed.