The U.S. Supreme Court on Monday declined to hear the case of Victor Saldaño, a Texas death row inmate whose intellectual disability is undisputed by both defense attorneys and the state’s own experts, paving the way for his execution in a case that has drawn scrutiny over whether the courts will allow a constitutional claim to be litigated on the merits.

Saldaño was convicted of murder in a 1996 robbery gone wrong in Texas. His trial attorneys did not raise the claim of intellectual disability at the time, the NPR reported. He was in the country illegally when the crime occurred. After his conviction, his case was referred to the Texas Office of Capital Forensic Writs, a state public defender’s office. Lawyers there determined that Saldaño had an IQ of 74, within the range that could qualify him for exemption from execution under the U.S. Constitution’s ban on executing people with intellectual disabilities.

Ben Wolff, the director of the Forensic Writs office, traveled to Argentina, where Saldaño was raised, to gather evidence. In an interview with NPR, Wolff said neighbors, family members, and former teachers all agreed that Saldaño exhibited delusional behavior and could not grasp basic tasks, such as how to cross a street without being struck by a car.

“Every expert who has evaluated Mr. Saldaño for intellectual disability agrees he’s intellectually disabled,” Wolff said in a statement. “The state of Texas, who several years ago sought Mr. Saldaño’s execution, now agrees that he meets the criteria for intellectual disability.”

Prosecutors representing the state of Texas reviewed the evidence and concurred that Saldaño should not be eligible for the death penalty. But the Texas Court of Criminal Appeals disagreed, ruling against Saldaño. His lawyers then appealed to the U.S. Supreme Court.

On Monday, the Supreme Court refused to hear the case in a 6-3 vote, with the court’s three liberal justices dissenting. The decision means Saldaño is likely to face execution unless his legal team secutes relief through another avenue.

“It is disappointing that the courts have yet to allow us through the courthouse doors to present what we believe to be overwhelming evidence that Mr. Saldaño is intellectually disabled and, as such, the U.S. Constitution forbids his execution,” Wolff said.

MSI previously reported that the Supreme Court dismissed Alabama’s bid to execute an inmate with borderline intellectual disability in a similar case last month. Saldaño’s attorneys said they will continue their efforts to prevent his execution.