Wichita ? A conservative group with ties to billionaire industrialists Charles and David Koch is spending big money to thank U.S. Rep. Mike Pompeo for his work in Congress amid a bitter race for his seat.

Americans for Prosperity says it’s spending $409,225 for radio and television ads that begin Tuesday and run until the day before the Aug. 5th Republican primary.

AFP state director Jeff Glendening says the group likes to show its appreciation to those who share its values. He cites Pompeo’s efforts to eliminate the wind production tax credit and control spending, as well as his opposition to earmarks.

Former Congressman Todd Tiahrt is challenging Pompeo in the 4th District. Tiahrt has criticized Pompeo for pursuing special interest agendas that have hurt the local economy.