The execution of a convicted killer from Puerto Rico took 34 minutes — twice as long as normal — because officials botched the insertion of the needles that delivered the lethal chemicals, a medical examiner said Friday.

Gov. Jeb Bush responded to Dr. William Hamilton's preliminary findings by halting the signing of more death warrants until a commission he created to examine the state's lethal injection process completed its final report by March 1. Bush said he wanted to ensure the process did not constitute cruel and unusual punishment — a claim that death penalty opponents have leveled in their bid to halt the state's use of the lethal injection.

Hamilton refused to say whether he thought Angel Nieves Diaz died a painful death.

"I am going to defer answers about pain and suffering until the autopsy is complete," Hamilton said during a conference call. He said further tests may take several weeks.

Hamilton, who performed an autopsy Thursday, said needles pierced two veins and then went into soft tissue in Diaz's arms.

"More likely than not, the perforation of the veins occurred very early in this process," Hamilton said. "The autopsy findings were different than any other lethal injections."

Hamilton also said that although there were records that Diaz had hepatitis, his liver appeared normal. State corrections officials said after Wednesday's execution that Diaz had liver disease, which caused him to metabolize the lethal drugs more slowly.

As a result of the chemicals going into his arms near the elbow, he had an 12-inch chemical burn on his right arm and an 11-inch chemical burn on his left arm, Hamilton said.

State Corrections Secretary James McDonough said the execution team did not see any swelling of the arms, which would have been an indication that the chemicals were going into tissues and not veins.

David Elliot, a spokesman for the National Coalition to Abolish the Death Penalty, said experts his group had contacted suspected that liver disease was not the explanation for the problem.

"Florida has certainly deservedly earned a reputation for being a state that conducts botched executions, whether its electrocution or lethal injection," Elliot said. "We just think the Florida death penalty system is broken from start to finish."