Carroll's credibility took a severe hit as a result of an investigation into an alleged insurance kickback scheme during the Ford administration and carrying on into his administration. When called before a grand jury in 1980, Carroll invoked the Fifth Amendment. He was not convicted of any wrongdoing, but his first state Democratic Party chairman, Howard P. "Sonny" Hunt, was after refusing to cooperate with the investigation. The probe also hurt commerce commissioner Terry McBrayer, Carroll's choice for governor in 1979. McBrayer finished third out of five candidates in the Democratic primary that year, won by late entry John Y. Brown Jr..