A Texas inmate scheduled to be executed Wednesday evening has insisted he wasn't involved in a San Antonio "lovers' lane" killing more than 14 years ago that sent him to death row.

Juan Edward Castillo was condemned for the fatal shooting and robbery of a 19-year-old man that testimony showed was carried out by Castillo and several friends on a secluded road where the victim was enticed by the promise of drugs and sex.

Castillo would be the 11th convicted killer put to death this year in the U.S. and the sixth given a lethal injection in Texas.

His appeals lawyers contended no physical evidence tied him to the slaying of Tommy Garcia Jr. and argued in appeals that trial testimony from witnesses who said he either told them about the slaying or they heard Castillo talk about committing the crime was false or misleading.

At his trial, two eyewitnesses testified they saw Castillo shoot Garcia, three people said they heard him talk about the killing and another witness testified he was wearing jewelry that belonged to the victim, prosecutors said.

The Texas parole board on Monday refused a clemency request and the U.S. Supreme Court and the Texas Court of Criminal Appeals, the state's highest criminal court, both refused appeals that focused on witness trial testimony that implicated Castillo.

Matthew Howard, an assistant district attorney in Bexar County, which includes San Antonio, argued that Castillo's lawyers had been unable to explain why Castillo, "a supposed innocent, was implicated in the robbery-murder by so many people."

It wasn't clear if any last-day appeals for Castillo would be filed in the courts. His lawyers didn't immediately respond to a message left Wednesday morning by The Associated Press. Howard said he wasn't aware of any new petitions.

Castillo, 36, in an interview last week from outside death row denied any involvement in Garcia's Dec. 3, 2003, killing and said he had "no idea" who fatally shot the San Antonio rapper with a reputation for carrying a lot of cash and wearing flashy jewelry.

"I was offered a plea bargain three times," Castillo told the AP. "I refused to plead guilty. ... I don't want to die but at the same time I would hate myself every day if I did that."

Testimony at Castillo's 2005 trial showed Castillo's girlfriend, Debra Espinosa, offered Garcia drugs and sex if he'd take her in his car to a San Antonio lovers' lane. Garcia didn't know he was being set up.

Once they were parked, testimony showed Castillo smashed a car window with the butt of his pistol, opened the door and demanded Garcia's money. But Garcia, also known as rapper J.R., refused and was shot.

Espinosa and Francisco Gonzales, who authorities said accompanied Castillo to the ambush, accepted 40-year prison terms in plea agreements. A fourth person, Teresa Quintero, pleaded no contest to a robbery charge and received 20 years. Testimony showed she was the driver who took Castillo and Gonzales to the dark San Antonio road for what was supposed to be a simple robbery.

Relatives said Castillo talked about the killing and a witness said she saw him a day later wearing a distinctive medallion on a thick gold chain that had belonged to Garcia. Castillo said last week from prison the jewelry was his, not Garcia's, and said Espinosa was not his girlfriend.

Castillo was 22 and already had been in prison on a two-year sentence for deadly conduct with a firearm when he was arrested for Garcia's killing. At his trial, the mother of Castillo's son told of repeated domestic violence incidents. Other witnesses linked him to shootings, robberies, assaults and drug dealing.