A South Carolina man, along with his wife, has been arrested for the death of a sex offender who hasn't done anything wrong to him or his family. He only knew about him, his offenses as well as personal information from the state registry.

Vigilante couple Jeremy Lee Moody and his wife, Christine, were charged with two counts each of murder over the deaths of Charles Marvin Parker and his wife, Gretchen Dawn. Mr Parker was a sex offender convicted of third-degree criminal sexual conduct that happened some 10 years earlier.

Asked why he targeted sex offenders and if he had a previous run-in with them, Mr Moody did not provide detailed answers. There are just people "I hate."

But Mr Moody did confess to investigators that he got Mr Parker's information from the state's registry, and that he randomly attacks sex offenders.

Jeremy Lee Moody and his wife, Christine, were charged with two counts each of murder over the deaths of a sex offender and his wife.

On Sunday, Mr Moody, who lived in Lockhart, went to the Jonesville home of Mr Parker and made a fake concern over his car just so he can be invited into the couple's house. Mr Parker was a mechanic.

"You think I'm here to rob you. I'm not here to rob you. I'm here to kill you because you are a child molester," Sheriff David Taylor quoted Mr Woody's narration during initial investigation talks.

He then allegedly shot and stabbed the couple. Mrs Parker, who was found to be an accomplice of her husband's sex offense against a mentally challenged woman in 2003, was killed because she just happened to be there at that time.

Mr Taylor said Mr Woody had originally planned to kill Mr Parker in 2012.

At the time he was arrested on Wednesday, Mr Woody was set to kill another sex offender.

"He planned to kill another sex offender on the register today," the sheriff said.