Has the state of Texas executed an innocent man? That question has lingered since Cameron Todd Willingham was put to death for killing his three children. Now a man exonerated and set free from death row tells our John Salazar the state got it wrong.

It's been more than a decade since Texas executed Cameron Todd Willingham.

"When I was there, almost 400 men were executed," said Anthony Graves, a board member of the Houston Forensic Science Center.

Anthony Graves was on death row in a separate case, exonerated five years ago for killing six people. Graves said he and Willingham were friends.

"When Todd was executed, it just reminded me of No. 1: How blessed I am. But No. 2: Just how much work we have to do," said Graves.

Willingham was convicted for the deaths of his three children in 1991. Prosecutors convinced a Navarro County jury that the Corsicana man set his house on fire, intentionally killing his kids.

After Willingham's execution, forensic science reports surfaced and provided overwhelming findings that he could not have set his house on fire. The prosecutor in the 1992 trial is now accused of prosecutorial misconduct by the Texas State Bar.

"We need to hold prosecutors accountable," said Graves.

Since his release from prison, Graves is active in criminal justice reform. Late last week, he spoke at the Forensic Technology Center of Excellence's Impression Pattern and Trace Evidence Symposium in San Antonio.

"This seems to be part of the solution and not the problem," said Graves.

Beyond his efforts to punish prosecutors who cheat at trial, Graves says he wants science strengthened.

"Obviously, our findings can be vital to the outcome of a criminal justice case," said Heidi Eldridge, a research forensic scientist with RTI International. "And so we want to make sure we're representing our evidence in a way that is appropriate and correct in its findings."

Junk science and a poor fire investigation helped convict Willingham, and a prosecutor may have put an innocent man to death. Graves insists more cases like Willingham's have yet to be uncovered.

"Todd wasn't the only man who had a strong claim to actual innocence that was executed. There are many more Todd Willinghams that are in the grave behind the state of Texas," said Graves.

The prosecutor in that case is former Navarro County Assistant District Attorney A. John Jackson. Jackson was charged with misconduct by the state bar in March, but he denies the claims.