Texas to execute man who killed boy and drank his blood
Gurney used for lethal injections (AFP)

A south Texas man who bludgeoned and slashed to death a 12-year-old boy, mutilated the corpse and said he drank the blood of his victim is set to be executed on Wednesday at the state's death chamber in Huntsville.

Pablo Vasquez, 38, is scheduled to be put to death by lethal injection at 6 p.m. If the execution goes ahead, it would be the sixth in Texas this year and the 537th since the U.S. Supreme Court reinstated the death penalty in 1976, the most of any state.

Lawyers for Vasquez have launched a last-minute appeal to halt the execution, saying in a petition filed with U.S. Supreme Court their client was denied a fair punishment because prospective, qualified jurors in his trial were dismissed if they had sympathies against the death penalty.

The lawyers also raised questions of ineffective counsel at trial and initial appeal. They have previously said Vasquez had mental health problems and suffered from learning disabilities.

The victim, David Cardenas, was found under metal sheets in the Texas border town of Donna in 1998. Arms were missing from the corpse, which had no skin on the back and a hole in the back of the head, court papers filed by Texas said.

The incident raised worries at the time about occult rituals, which were stoked when prosecutors produced a taped confession in which Vasquez, then 21, admitted to the killing and drinking his victim's blood after saying voices from the devil told him to do so.

Cardenas, trying to fit in with a group of teenagers and Vasquez, was hanging out with the group near a mobile home, when he was attacked in 1998.

Police later received tips of a murder and found the decaying and mutilated body of the 12-year-old, the court papers showed.

Prosecutors said Vasquez hit the victim in the head with a pipe and cut his throat. They also said he stole some jewelry from the victim.

"The body was also mutilated after death by some means that caused bones to shatter," the court papers said.

It took the jury about an hour to find Vasquez guilty.

A co-defendant, then 15, was sentenced to 35 years in prison on a murder conviction.

(Reporting by Jon Herskovitz; Editing by Sandra Maler)