The Iowa City Press-Citizen newspaper reported on Friday that Rayhons was charged with third-degree sexual abuse, a felony, in connection with an incident at his wife's nursing home on May 23.
A criminal complaint filed against Rayhons, 78, said that he was told on May 15 that his wife, Donna, "did not have the cognitive ability to give consent to any sexual activity," the newspaper reported.
The complaint, according to the Press-Citizen, said Rayhons visited his wife on the date in question and pulled the curtain closed in her room. The wife's roommate later told authorities that she heard noises that led her to believe Rayhons was having sex with his wife, the newspaper reported.
The complaint also said there was surveillance video showing Rayhons "leaving his wife's room and discarding undergarments," according to the Press-Citizen.
The newspaper said the couple was married in 2007 and Donna Rayhons died on Aug. 8 at age 78.
The Press-Citizen reported that the case will be prosecuted by the state Attorney General's Office. Rayhons has not resigned his seat, but earlier this year announced he would not be seeking reelection.