When the former Republican governor of Kentucky Matt Bevin was asked in a recent radio interview how he could justify having pardoned on his last day in office a child rapist, he replied: “Which one?”

The interview went downhill from there. Bevin said he had allowed Micah Schoettle, 41, who was serving a 23-year sentence for rape, and other sexual offenses to walk free last week after less than 18 months in prison because his nine-year-old victim had been found to have her hymen intact.

“There was zero evidence,” Bevin said.

The former governor has come under an avalanche of criticism after pardoning 428 people in the final days of his term after he was narrowly voted out of office in November. Among those who were set free were two convicted child rapists and several murderers and other violent criminals.

In his radio interview Bevin revealed that Schoettle had been accused of raping the nine-year-old girl repeatedly over two years, often with her sister present in the room. He said: “Both their hymens were intact. This is perhaps more specific than people would want, but trust me. If you have been repeatedly sexually violated as a small child by an adult, there are going to be repercussions of that physically and medically.”

As word of Bevin’s self-justification circulated, medical and other experts lined up to state that Bevin’s science was all wrong.

George Nichols, former chief medical examiner for Kentucky, told the Courier Journal: “Rape is not proved by hymen penetration. He not only doesn’t know the law, in my humble opinion, he clearly doesn’t know medicine and anatomy.”

Rob Sanders, who prosecuted the Schoettle case, accused the former governor of being “ignorant of the medicine and science in child rape cases”. He said the question of whether the victim would show any sign of injury was the subject of eight hours of intense testimony during the trial that “Matt Bevin obviously never watched”.

Executive pardons have long been a focus of fierce public debate. Bill Clinton was consumed by “Pardongate” after he used his last day in the White House in 2001 to commute the sentences of several people including Marc Rich, a fugitive fraudster whose family donated large sums to the Democratic party. Donald Trump has also come under fire for making presidential pardons including that of Scooter Libby, former chief of staff to former vicepresident Dick Cheney who had been convicted of perjury and obstruction.

But the mountain of pardons issued by the former governor of Kentucky stands in a class of its own. Among the 428 individuals to benefit from the orders are many that have left local law enforcers and judicial experts aghast.

Among the gruesome violent crimes committed by those pardoned are the beheading of a woman whose body was hidden in an oil drum and a newborn baby dumped by their mother in a septic tank. Another pardon that has attracted enormous opprobrium in the state is that of Patrick Baker, who was set free having served two years of a 19-year sentence for reckless homicide.

The Courier Journal later discovered that the prisoner’s family had donated $21,500 for Bevin’s 2015 governor’s campaign.

The mother of Schoettle’s child victim, who is not being named, told the Cincinnati outlet WCPO that his release had been a “slap in the face. It feels like we’re going through it all over again … we just got to the point where we felt safe leaving the house and not looking over our shoulders.”

She said that when she had informed her daughter that her attacker had been pardoned and set free, the girl replied: “Well, it figures. They always get away with it.”