Exoneree Dale Lincoln Duke with Dallas County District Attorney Craig Watkins. (credit: CBSDFW.COM)

DALLAS (CBSDFW.COM) – Dallas County District Attorney Craig Watkins was commenting on the court-ordered release of a convicted murderer who spent years in prison for a killing he didn’t commit when he made an emotional statement.

“People don’t know my great-grandfather was executed by this state,” Watkins announced.

Watkins made the statement while commenting about the series of exonerations of Dallas men sent to prison for decades.

He said the same concern he’s shown for wrongful convictions should be shown for capital punishment cases.

“When we have all these men that have been exonerated for crimes they didn’t commit, have we executed someone in this state who didn’t commit the crime?” Watkins questioned.

The statements generated a whirlwind of phone calls to Watkins’ office.

People have asked if the top law enforcement officer of Dallas County is calling for the end of capital punishment. Friday morning, Watkins sat down for a 30-minute interview to provide clarity to his statements.

“It was a dark secret of our family,” Watkins said of the story of Richard Johnson’s execution.

Johnson is Watkins’ maternal great-grandfather. According to the district attorney, Johnson was executed for a murder in 1931.

“I’m still researching the details,” he said, when asked if he believed his great-grandfather was executed for a crime he didn’t commit.

But Watkins said he shared the story in the effort to raise awareness about wrongful convictions, and the possibility of someone facing execution in Texas for a crime they didn’t commit.

“Are we going to allow an individual who may be innocent, to go to prison? We’ve allowed individuals who were innocent to go to prison,” he said. “I think the conventional wisdom tell us, we’ve had someone in this state executed that shouldn’t have been.”

Watkins is nationally recognized in the criminal justice arena for his implementation of the District Attorney’s Conviction Integrity Unit.

The unit investigates cases prosecuted in Dallas County that have possible indications of wrongful convictions.

More than one dozen Dallas County men have been freed from prison, after being exonerated from crimes they didn’t commit.

Most of those cases are cleared through DNA analysis, proving the innocence of the person convicted of the crime.

On Wednesday, Richard Miles walked from a Dallas County courtroom free from a 40 year prison sentence for murder.

Miles spent 15 years behind bars until advocates proved critical evidence clearing his name was never handed over to defense attorneys.

Watkins used Miles’s murder case exoneration to air his concerns about death penalty cases.

“Our office continues to handle capital punishment cases”, he says. “My argument isn’t a moral argument. It’s a logistical argument. Can we say whether a mistake can be made?”