The Texas Supreme Court has blocked Robert Roberson's ...

An unusual legal move bought more time for a Texas man who was set to be executed on Thursday evening.

A bipartisan group of Texas lawmakers, who said Robert Roberson was actually innocent and shouldn’t be executed, issued a subpoena for the death row inmate.

Roberson was convicted of the capital murder of his 2-year-old daughter in 2002. Prosecutors said she died from shaken baby syndrome but new evidence showed she died from pneumonia and not abuse. That new evidence was not considered in any of his rejected appeals.

"For over 20 years, Robert Roberson has spent 23.5 hours of every single day in solitary confinement in a cell no bigger than the closets of most Texans, longing and striving to be heard. And while some courthouses may have failed him, the Texas House has not." said Texas Reps. Jeff Leach (R-Plano) and Joe Moody (D-El Paso) in a joint statement.

The lawmakers said they subpoenaed Roberson to hear his testimony on Texas capital punishment. Roberson was scheduled to testify on Monday, Oct. 21, several days after the scheduled execution of 6 p.m. Thursday.

Just 90 minutes before the death warrant was to be carried out, a Travis County judge presided over a court hearing to decide which carried more weight and should be honored — a Texas legislative subpoena or a death warrant for execution.

Judge Jessica Mangrum granted a temporary restraining order to prevent the execution. This began a night of legal limbo for Roberson.

The state, intent on going through with the execution, succeeded in having Mangrum's restraining order overruled by the Texas Criminal Court of Appeals.

The lawmakers then appealed to the Texas Supreme Court, arguing their effort to subpoena Roberson was a civil matter. The state's highest court agreed.

"Whether the legislature may use its authority to compel the attendance of witnesses to block the executive branch’s authority to enforce a sentence of death is a question of Texas civil law, not its criminal law," wrote Justice Evan Young.

"Must the executive yield if the legislature invokes its authority — that is, would proceeding with an execution in these circumstances entail the executive branch’s intrusion into the broad authority of the legislative branch?" Young continued. "Or, contrariwise, would allowing various committees of the legislature to subpoena an inmate who is subject to an impending death sentence constitute the legislative branch’s intrusion into the orderly functioning of the law, risking manipulation of the judicial process and the executive function?"

The Supreme Court left it to the Travis County District Court to resolve the separation of powers issue.

It remained unclear when a new execution date would be scheduled. The death warrant for Roberson expired at midnight Friday.

Meanwhile, Roberson, who has been on death row for 22 years, will live another day.

"We're deeply grateful to the Texas Supreme Court for respecting the role of the Texas legislature in such consequential matters," said Leach and Moody. "We look forward to welcoming Robert to the Texas Capitol, and along with 31 million Texans, finally giving him — and the truth — a chance to be heard."