A Texas inmate serving life for murder managed to break free from his shackles, overpower a bus driver and escape from custody, officials said.

Gonzalo Lopez, 46, was on a transport bus en route from Gatesville to Huntsville for a medical appointment when he escaped in Leon County on Thursday, the Texas Department of Criminal Justice said.

Two officers were on the bus: one at the front as well as one in the back who was armed with a shotgun, Texas Department of Criminal Justice spokesman Robert Hurst told reporters.

Lopez “was somehow able to get out of his shackles and get into the driver’s compartment of the bus,” Hurst said.

Lopez “was able to overpower the driver. There was a struggle … the bus went off the roadway,” Hurst said.

The officer driving the bus was stabbed in the hand and suffered a non-life-threatening injury, he added.

Lopez then jumped off the bus and fled, Hurst said.

Lopez is serving a life sentence for a capital murder in Hidalgo County and an attempted capital murder in Webb County, the Texas Department of Criminal Justice said. The murder was committed with a pickaxe, Hurst said.

“We do not know if he has obtained any kind of a weapon,” Hurst said. “Last we saw him he did not appear to have a weapon in his possession, but who knows what he might’ve been able to get.”

Centerville School District schools are closed on Friday as the search continues.

Leon County is about 130 miles south of Dallas. The Leon County Sheriff’s Office urged local residents to lock their homes and cars. Anyone who sees Lopez is asked to call 911 and not approach him.