TUPELO, Miss. (WCBI)-A Tupelo man is back behind bars for allegedly exposing a juvenile to HIV. 29 year-old Robert Gardner was charged Tuesday with sexual battery and knowingly exposing a juvenile to HIV. Reports indicate that Gardner engaged in sexual acts with a 15 year-old girl last week. Gardner was just released from prison three months ago, where he served a three year sentence for similar charges. Gardner was charged in February 2010 with having unprotected sex with at least 2 women while knowing he is HIV positive. His bond is set at one million dollars.