Hawkins County Sheriff Ronnie Lawson said Harr turned herself in around 4:30 p.m. Saturday afternoon.
Harr's husband, Randy Harr, 43, was found in Florida on Thursday, just after being named to the Tennessee Bureau of Investigation's Top Ten List. He is charged with first degree murder, aggravated burglary and arson.
James Hall, 52, was at the Sullivan County jail at the time he was named as a suspect. He is also charged with intent to interfere with an arrest.
Varelli was found dead in the bathroom of his Stanley Valley home with multiple gunshot wounds in March.