San Francisco ? State officials on Tuesday postponed indefinitely the execution of a condemned killer, saying they would be unable to comply with a judge’s order that a medical professional administer the lethal injection.

Prison authorities called off the execution after failing to find a person licensed to inject medications to give a fatal dose of barbiturate, said Vernell Crittendon, a spokesman for San Quentin State Prison.

“We are unable to have a licensed medical professional come forward to inject the medication intravenously, causing the life to end,” he said.

It was unclear when the execution would be carried out, but the delay could last for months because of legal questions surrounding California’s method of lethal injection.

The 24-hour death warrant for Michael Morales was set to expire at 11:59 p.m. Tuesday. After that, state officials have to go back to the trial judge who imposed the death sentence in 1983 for another warrant.

Morales, 46, was supposed to die by lethal injection at 12:01 a.m. But the execution was put off until Tuesday night after two anesthesiologists objected that they might have to advise the executioner if the inmate woke up or appeared to suffer pain.

“Any such intervention would clearly be medically unethical,” the doctors, whose identities were not released, said in a statement. “As a result, we have withdrawn from participation in this current process.”

The doctors had been brought in by a federal judge after Morales’ attorneys argued that the three-part lethal injection process violates the Eighth Amendment prohibition against cruel and unusual punishment. The attorneys said a prisoner could feel excruciating pain from the last two chemicals if he were not fully sedated.

U.S. District Judge Jeremy Fogel gave prison officials a choice last week: bring in doctors to ensure Morales was properly anesthetized, or skip the usual paralyzing and heart-stopping drugs and execute him with an overdose of a sedative.

Prison officials had planned to press forward with the execution Tuesday night using the second option. The judge approved that decision, but said the sedative must be administered in the execution chamber by a person who is licensed by the state to inject medications intravenously. That group would include doctors, nurses and other medical technicians.

The state notified the 9th U.S. Circuit Court of Appeals late Tuesday afternoon that it did not intend to go forward with the execution, said Cathy Catterson, a clerk for the 9th Circuit.

Morales was condemned in 1983 for killing 17-year-old Terri Winchell, who was attacked with a hammer, stabbed and left to die half-naked in a vineyard.

The victim’s mother, Barbara Christian, was outraged by the repeated delays.

“I’m totally disillusioned with the justice system. We’ve been waiting 25 years with the expectancy that he is gonna pay for his crimes,” she said. “It feels like we just got punched in the stomach.”