Texas is set to execute Ivan Cantu on Wednesday. But is he guilty?

Cantu was found guilty of shooting and killing his cousin, James Mosqueda, and Mosqueda's fiancée Amy Kitchen in 2000. But mounting exculpatory evidence has cast doubt on Cantu's guilt and put pressure on the state to grant Cantu a reprieve.

AUSTIN (Nexstar) -- As the sun sets on Feb. 28, the State of Texas will end Ivan Cantu's 50 years of life in a Huntsville death chamber -- the ultimate punishment for the two lives he was convicted of taking more than two decades ago. But those who condemned him to death are now calling on the state to save his life.

Cantu was found guilty of shooting and killing his cousin, James Mosqueda, and Mosqueda's fiancée Amy Kitchen in 2000. But mounting exculpatory evidence has cast doubt on Cantu's guilt and put pressure on the state to grant Cantu a reprieve.

"The trial itself was fabricated. That's the simple fact. And it's not over yet," said Jeff Calhoun, who served as the jury's foreperson and found him guilty. He said the mountain of evidence presented against Cantu would have made it hard to render any other verdict.

Since then, however, the state's star witness -- the brother of Cantu's girlfriend -- admitted to lying on the stand. Several other pieces of evidence, including the victims' time of death and alleged statements Cantu made to other witnesses -- have contradicted the evidence presented in the original trial.

"The simple fact is that there was perjury committed in the case," Calhoun said. "It feels like it's my moral obligation to try to see this through... I'm suggesting that the execution be delayed until these other things can be explored."

Cantu has maintained his innocence for all 24 years he has been incarcerated. Yet, the Collin County District Attorney has maintained they got it right.

"I remain fully convinced that Ivan Cantu brutally murdered two innocent victims in 2000," District Attorney Greg Willis told CNN. "My belief is anchored in the undeniable evidence presented at trial."

Matt Duff, a private investigator who has been documenting disparities in the prosecution's case, said the evidence he has uncovered demands a rehearing.

"If it's extraordinary new evidence, it still can be slid in with hours to go. So that's where we're at," Duff said. "To kill a person under these circumstances is outrageous."

Texas executes more prisoners than any other state at 586 executions since 1982, but 16 people have been exonerated before being put to death. Cantu would be the 587th person executed in the state. Texas represents the third-most exonerations of death row prisoners, just behind Illinois and Florida, for a rate of almost 3%.

Nationwide, 196 people on death row have been exonerated in the last 50 years -- an average of almost four every year. Sixteen of those wrongfully convicted prisoners have been in Texas.

On Tuesday, the state's Court of Criminal Appeals denied Cantu's motion to stay his execution. Barring a reprieve from the governor, Cantu's execution is scheduled to go forward Wednesday evening.