District attorneys in both Harris and Montgomery counties requested the stay amid Shore's claim that another death row inmate tried to persuade him to confess to a murder he did not commit.
Shore, also known as the Tourniquet Killer, said that fellow inmate Larry Ray Swearingen convinced him to take responsibility for the murder of Melissa Trotter after they became friends in prison.
Swearingen is set to be executed for Trotter's 1998 murder in four weeks. He has repeatedly asserted his innocence.
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Prosecutors said Shore had planned to follow through with the plan -- which could have potentially set the stage for Swearingen to be exonerated -- until just before Shore's scheduled execution date, Oct. 18.
Over the summer, investigators conducted a search of Shore's cell as part of an inquiry into his mental health. In his cell, they found copies of court exhibits, scene photographs and handwritten documents pertaining to Trotter's murder.
Shore claimed that Swearingen provided him with the documents in order to make the confession more convincing, prosecutors said. The handwriting on the documents was "dissimilar to Shore's distinctive handwriting," according to prosecutors, but similar to Swearingen's handwriting.
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Claims made by Shore were corroborated during an interview with a woman who visited him in prison. Investigators said she knew he planned to confess and that he was aware of the location of evidence pertaining to Trotter's murder.
"Due to the untimely nature of the information, the veracity of any of those statements cannot be determined without this temporary reprieve," added Montgomery County District Attorney Brett Ligon.
"Given Shore's status as a serial killer, Shore's possession of these documents generated the remote possibility that Shore had some kind of involvement in Trotter's death," added Harris County District Attorney Kim Ogg. "It is always the first responsibility of prosecutors to see that justice is done."
Ogg said Shore's execution has been rescheduled for Jan. 18, 2018, the earliest legally available date.
Shore was dubbed the Tourniquet Killer after the way he strangled his victims with handmade tourniquets. He was convicted and sentenced to death in 2004 after prosecutors said he confessed to the murders of four females ranging in age from 9 to 21 between 1986 and 1995.
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