HOUSTON, Texas (KTRK) -- Houston Public Library is apologizing after a man charged for sexually assaulting a child was allowed to entertain children at Drag Queen storytime.The library said Friday that a review revealed the volunteer never completed a background check before he was allowed to participate in the program.Albert Alfonso Garza, 32, was last seen reading to children at the Montrose Library in September 2018.ABC13 Eyewitness News has learned Garza was charged with child sex assault in 2008. According to records, his victim was a child under the age of 14 years old.The library said appropriate action is being taken to ensure every participant in every program is verified to ensure similar incidents cannot happen in the future.Each program is supervised by staff, and all children are accompanied by a parent or guardian, the library said.