Austin, Texas ? A convicted killer facing lethal injection beat the executioner to it Thursday, committing suicide by slitting his throat and arm with a blade in his Texas death row cell 15 hours before he was supposed to die.

Michael Dewayne Johnson, 29, was found in a pool of blood by officers making routine checks on him every 15 minutes, authorities said. He was pronounced dead at a hospital.

Johnson had been set to die for the 1995 slaying of Jeff Wetterman, 27, gunned down at his family-run gasoline station and convenience store near Waco.

He used a sharp piece of metal attached to what looked like a wooden Popsicle stick, Lyons said.

It was unclear if the cutting edge was a razor blade or a sharpened piece of metal, or where he got it, authorities said. Some inmates are allowed to check out a razor blade to shave but must return it to a guard when they are finished, Lyons said.