They will ask the court to determine that there is probable cause to believe that Mr. Anderson withheld reports that the judge in the 1987 trial had ordered him to turn over. The judge had demanded the documents to determine whether they might help Mr. Morton’s case. Finding nothing exculpatory in the small number of documents he was provided by the prosecutor, the judge ordered the record sealed.

In August, however, a different judge ordered the record unsealed, and Mr. Morton’s lawyers discovered that Mr. Anderson had provided only a fraction of the available evidence. Missing from the file was the transcript of a telephone conversation between a sheriff’s deputy and Mr. Morton’s mother-in-law in which she reported that her 3-year-old grandson had seen a “monster” — who was not his father — attack and kill his mother.

Also missing were police reports from Mr. Morton’s neighbors, who said they had seen a man in a green van repeatedly park near their home and walk into the woods behind their house. And there were even reports, also never turned over, that Mrs. Morton’s credit card had been used and a check with her forged signature cashed after her death.

In October, Judge Sid Harle of Bexar County District Court freed Mr. Morton based on the DNA evidence and authorized an unusual process allowing his defense lawyers to investigate the prosecutor’s conduct in the original trial. The lawyers questioned the lead sheriff’s investigator, an assistant district attorney who worked with Mr. Anderson and the former prosecutor himself.

In their accounts, the witnesses said Mr. Anderson had firmly controlled every detail of the prosecution. In his own two-day deposition, however, Judge Anderson said he recalled few details of the case and asserted that he had done nothing wrong. He said that he had interpreted the judge’s order to disclose the reports as a narrow demand for the initial documents from the investigation and that he felt “sick” over Mr. Morton’s wrongful imprisonment.

If the court of inquiry ends with a finding that Mr. Anderson committed serious acts of misconduct by concealing material evidence, it could lead to disciplinary action by the state bar association and possibly even a criminal prosecution.