Revisiting the DNA, Once More The latest attorney to take on Perez's case is Marcy Greer. The Austin civil appellate attorney received a request from the District Court in the summer of 2012, asking that she look into allegations that Khan had abandoned Perez. She took over in early August and by Aug. 29 had filed a motion urging Yeakel to vacate his March judgment and issue a new ruling – one that could be appealed by an attorney who hadn't abandoned their client. Yeakel complied, and on Dec. 12 issued a new judgment, which Greer and her team contested within the month. The filings opened the case again, and gave Greer and her team time to sort through the seven boxes of case files that have accumulated since the murders. She's fought off perilous deadlines. In Nov. 2012, Hon. Karen Sage, the presiding judge over the 299th District Court (where Perez was tried and convicted) hadn't yet learned of Greer's Aug. 2012 motion to reopen the case, and signed a death warrant for his execution, effective March 21, 2013. (The order was quickly withdrawn.) The case has since failed at both the 5th Circuit Court of Appeals and U.S. Supreme Court. Shortly after appealing Yeakel's ruling and delaying the impending death date, Greer filed four unopposed motions in Sage's district court that would change the course of Perez's effort. The motions, filed July 19, 2013, called for the Travis County District Attorney's Office to provide Perez with a series of previously unreleased documents from his case, including the transcripts from his grand jury trial and any bench notes, data, or electropherograms taken or previously held by the District Attorney. The filings also included a motion requesting that the Tarrant County Medical Examiner run additional post-conviction DNA testing on six items – the two pairs of pantyhose used to strangle and bind Mitchell, fingernail scrapings from both of Mitchell's hands, the comal's handle, and the full length of the telephone cord – and that the Tarrant County crime lab test three other items that have yet to be analyzed by any lab – Mitchell's shirt, the Nike shoe sole, and a broken, bloody plant stand, which investigators concluded shattered during Barz's struggle before her death. (Since 2001, the Texas Code of Criminal Procedure has granted defendants the right to submit motions for additional DNA testing to their convicting courts so long as any revelation of DNA evidence could cast doubt on a convict's guilt. It also grants defendants the right to obtain grand jury transcripts from their case if it's believed the prosecution committed a Brady violation – that is, hid evidence favorable to the defense.) "Several of these items of physical evidence were analyzed multiple times, but only the final report and selected excerpts of the underlying testing data were available to the defense team for analysis," wrote Greer, citing Dr. Benjamin's letter from Oct. 2001. "Having access to all of the underlying data – not just the reports prepared for the trial and the habeas hearing – will allow a thorough and complete review of the evidence that was used to convict Perez and may also potentially inform the results of the new testing that Perez is seeking in order to draw out a profile of the real killer from the various incomplete and mixed DNA contributions on these items." Greer listed the significant number of fingerprints lifted "from highly sensitive locations" around the house, including the "blood-covered bathrooms and bedrooms where two of the bodies were found" that were never matched to Perez or any of the victims. She noted "other leads that may have identified the real killer in this case, including information about witness interviews and background investigations," as well as information about any attempts the prosecution made to verify Perez's whereabouts during the murders. Buddy Meyer, who assisted Dawson-Brown at trial, denies Greer's accusations that "Perez became the focal point of the case early and to the exclusion of evidence suggesting his innocence or another possible perpetrator." However, he told the Chronicle that the D.A.'s Office has no reason to oppose new testing. "You're talking about a death penalty case here," he said. "Why would we not agree to post-conviction testing? We're talking about a man's life."more
In October, Perez received a letter from District Attorney Rosemary Lehmberg informing him that his case "may be impacted by recent scientific concerns involving the historical interpretation of DNA results." Lehmberg attached to her letter a notice from Texas Forensic Science Commission presiding officer Vincent Di Maio, which was sent to state and local law enforcement agencies on Aug. 21, 2015. Di Maio said there are "concerns [involving] the interpretation of DNA results where multiple contributors may be present." Included in his letter is an explanation of the FBI's May 2015 announcement that it had found "minor discrepancies" in its population database. (In May 2015, The Washington Post reported that 3% of DNA profiles the FBI had examined since 1999 were potentially affected.) On Jan. 28, the developments prompted Sage to issue a stay on Perez's execution. She sent a letter to Sian Schilhab, general counsel for Texas' Court of Criminal Appeals, indicating that the state has discovered "some potential Brady material in this case and has disclosed that evidence to the defense." Greer stresses that Sage hasn't found anything definitive yet, but that the three parties are working together "to try to identify where the holes are" in Perez's case. "I don't have all the documents necessary to complete the assessment," she said. "But there is a lot that does not add up about [Perez's] conviction: the evidence in the case, the way the crime scene was processed, and the Medical Examiner's reports." Perez says that he's "optimistic" about any potential revelations but refuses to get his hopes up. "I don't allow myself to get excited," he says. "I could.