( CNN ) -- Texas authorities on Sunday were searching for a convicted burglar who escaped from a medical facility by rappelling off the building using a string of bedsheets , officials said . Joshua Duane Barnes , 21 , was serving 35 years in prison for several convictions , including two escape charges . Joshua Duane Barnes , 21 , was last seen at 8:15 p.m. Saturday on the seventh floor of a Texas Department of Criminal Justice medical facility in Galveston , Texas , said TDCJ spokesman Jason Clark . Fifteen minutes later , Barnes was gone , Clark told CNN . Security officers noticed there was a hole in the wall and a vent had been removed . According to Clark , Barnes busted a hole through a wall in his room and then broke through a thick window . He apparently tied bedsheets together , rappelled down the side of the building to a roof , and then jumped to the ground , Clark said . Barnes was serving 35 years in prison for several felony convictions , including seven burglary charges , two escape charges and an aggravated assault charge in the Texas Panhandle area , according to a TDCJ press release . The inmate was being housed at a prison in Midway , Texas . He was transported to the medical facility in Galveston last week after being hurt in an altercation , TDCJ said . The department of criminal justice has tracking dogs and dozens of officers searching the area , Clark said . Local police officers also joined the search . Barnes began serving his sentence in January . CNN 's Chuck Johnston contributed to this report .
Joshua Duane Barnes , 21 , was last seen on 7th floor at Texas medical facility . He apparently tied bedsheets together and exited window , police official says . Comment: