Arizona officials filed an appeal Monday just hours after a federal judge blocked an execution set for Tuesday on grounds that more time was needed to consider a challenge to the use of a knockout drug from an unidentified manufacturer.
The state's appeal argued that Silver made faulty assumptions and disregarded provisions of the execution protocol that ensure inmates will be unconscious before other drugs are administered to paralyze their muscles and stop their heart.
Landrigan's lawyers contend he could be suffocated painfully if the sodium thiopental didn't render him unconscious.
Silver ruled that was a legitimate concern and blocked the execution of Landrigan, who was convicted of the 1989 strangulation and stabbing death of Chester Dyer of Phoenix in a killing prosecutors said was part of a robbery.
The assumption of the state's three-drug execution protocol "is that the sodium thiopental will, in fact, be sodium thiopental and it will operate in its intended manner," Silver wrote.
The drug is in short supply nationally.
A ruling also was due from the state Supreme Court on the separate issue of whether Landrigan is entitled to a hearing on newly available DNA evidence. The justices were considering an appeal of a trial judge's refusal to hold a hearing.
Landrigan's lawyers said the new test results, which found DNA from only Dyer and a person other than Landrigan on certain crime-scene evidence, bolster his claim of innocence and justify holding a hearing. Prosecutors contend that another person was present at the murder in Dyer's apartment and the new test results don't change anything.
The state Supreme Court was expected to rule on the DNA issue by Tuesday morning, spokeswoman Jennifer Liewer said. The justices understand the urgency of the matter, she said.
A 9th Circuit panel on Monday rejected Landrigan's request for a stay of execution based on the DNA issue. The new evidence failed to show that Landrigan didn't participate in the killing, the order said.
On the drug issue, Silver also ordered prosecutors to provide Landrigan's lawyers with information about the manufacturers of the drugs to be used. Responding to an earlier order by Silver, prosecutors had submitted that information only to her, asking that it be kept confidential.
Landrigan attorney Dale Baich welcomed Silver's order.
"Obviously the court has some concerns here and wants to take a closer look at this issue," he said.
Baich commented after visiting his client at a prison in Florence. Landrigan was aware of the ruling but the lawyer declined to discuss what was said.
Silver said a state law providing confidentiality for executions and those involved in carrying out executions to protect them from harassment doesn't extend to the drug manufacturers.
Another federal judge in Phoenix upheld the state's three-drug execution protocol in 2009. That ruling followed a U.S. Supreme Court ruling allowing a similar protocol used by Kentucky.
While not publicly identifying the manufacturer of the state's supply of sodium thiopental, state officials have said the drug has a May 2014 expiration date, was not produced by the sole U.S. manufacturer, and was procured through processes approved by U.S. Customs and U.S. Food and Drug Administration officials.
Landrigan filed an inmate civil rights lawsuit over the drug issue Thursday after a state prosecutor disclosed during a court hearing a day earlier that the U.S. manufacturer didn't make the drug.
Arizona's last execution was in 2007.