Evil sex pervert Ariel Castro was obsessed with slain child beauty queen JonBenet Ramsey and kidnap victim Elizabeth Smart!

Michelle Knight, one of three hostages Castro kept in his house of horrors, reveals that the degenerate monster once whined that he wished he’d snatched the two tragic youngsters.

“Hr told me, ‘I wish I had gotten to that little JonBenet Ramsey first,’” Knight, 33, writes in her just-published memoir, “Finding Me.”

“Another time he made the same kind of comment about Elizabeth Smart, who was abducted just two months before I was. ‘I know, I’m a sick man,’ he said. ‘I hate how I am.’”

Six-year-old JonBenet was murdered in her Boulder, Colo., home in 1996, while 14-year-old Elizabeth was abducted from her bedroom in Salt Lake City, Utah, in 2002.

While JonBenet’s slaying remains unsolved, Elizabeth was rescued nine months after being taken. Her cap­tors – religious drifter Brian David Mitchell and his wife Wanda Barzee – are in jail.

After more than 10 years of hell in Castro’s home in Cleveland, Knight and fel­low victims Amanda Berry and Gina DeJesus were rescued in May 2013.

C a s t r o was sen­tenced to life in prison without pa­role plus 1,000 years. But the cowardly brute, 53, committed suicide by hanging himself with bed sheets after a month be­hind bars.

Gutsy Knight has since rebuilt her life. In her book, she describes her first hours after being kidnapped, when Castro strung her from a wire hung between two poles. Two days later, he returned to brutally rape her. “I was in so much shock and fear that all I could do was lie there like I was dead,” she writes.

A source told The ENQUIRER: “It’s awful to contemplate JonBenet and Elizabeth in that devil’s hands. Their families must be terrified to think of the torture they might have endured.”