AUSTIN - Federal appellate judges Tuesday appeared sympathetic to arguments that condemned inmate Anthony Graves might have avoided conviction for the murders of a woman and five children if prosecutors hadn't withheld crucial evidence.

Prosecutors relied heavily on convicted killer Robert Earl Carter's testimony that Graves aided him in the slayings, U.S. Circuit Judge W. Eugene Davis interjected as Assistant Texas Attorney General Kelli Weaver defended the guilty verdict.

"That statement blew that (testimony) out of the water," Davis said about Carter's statement, on the night before he testified, that he alone had committed the murders. Prosecutors withheld the statement from the defense.

Graves was convicted largely on the testimony of Carter and three jailers who said they had heard incriminating comments by Graves. No physical evidence linked Graves to the crime.

Carter recanted his testimony in a deposition in 2000 and said, moments before his execution in May that year, that "Anthony Graves had nothing to do with it. I lied on him in court."

In Tuesday's hearing, U.S. Circuit Judge Jacques Wiener questioned the jailers' testimony. After Weaver said the testimony was important, Wiener remarked: "You haven't been around the same jailers I have."

Graves could get a new trial if the three-judge panel of the 5th U.S. Circuit Court of Appeals agrees that prosecutors' case would have been weakened if the jury had known about Carter's statements that Graves was not involved in the 1992 murders and that his own wife, Theresa "Cookie" Carter, was.

Bobbie Davis, 45, her 16-year-old daughter, Nicole, and Davis' four grandchildren, ages 4 to 9, were killed in August 1992 in Somerville, north of Brenham.

Charles Sebesta, who at the time of the trial was district attorney for Washington and Burleson counties, said in a telephone interview Tuesday that he did not hide testimony from the defense.

"I want the facts to come out," Sebesta said. "I want the truth to be known.

"Graves was the worst one," he added. "Graves was the one with the knife. Carter told us that."

Also attending the hearing were several journalism students from the University of St. Thomas in Houston, participants in the University of Houston-based Innocence Network, who have unearthed evidence that they say shows Graves' innocence.

Their adviser, journalism professor Nicole Casarez, revealed a letter that she said she obtained just before the Tuesday hearing in which Sebesta wrote about the interrogation of Carter the night before the trial. The letter notes the importance of an assistant's work in questioning Carter.

"This examination ... was instrumental in 'breaking' down Carter's resistance and facilitating testimony, testimony which, in post-verdict interviews with jurors, was absolutely essential in their minds, toward corroborating a largely circumstantial case," the letter states.

Graves' appeals attorney, Roy Greenwood, did not use the letter in his argument, but said it confirmed his point.

harvey.rice@chron.com