DOC is well-known for detailing everything except, apparently, what happens at an execution

Department spokeswoman Gretl Plessinger said Diaz had liver disease and that medical condition required the second dose of chemicals. Diaz's lawyers and family, meanwhile, said he was not sick.

"It was not unanticipated that the metabolism of the drugs would take additional time," Plessinger said. "As indicated in our execution protocol, a second series of drugs can be introduced, and that occurred."

A national expert on lethal injections, however, said the department's explanation "makes absolute zero sense." Jonathan Groner, associate professor of surgery at The Ohio State University College of Medicine and Public Health, said the quick- but short-acting anesthesia would not metabolize, or break down, in a diseased liver. Therefore, it would have a more potent effect on a person with liver disease.

"What would be acceptable for a normal person might be an overdose for a person with liver disease," Groner said. "That means (Diaz) should have gone done faster or stayed down longer because the drug hangs around longer."

He surmised that corrections officials either mixed or injected the anesthesia incorrectly, or didn't have the IV properly inserted.

Plessinger would not comment on the speculation, but confirmed that at least one other condemned inmate had been injected with a second dose of lethal chemicals. She could not, however, say when. That angered death penalty lawyers who have been arguing that the Department of Corrections adopted new protocols for lethal injections in August in secret, and without review or accountability.

"DOC is well-known for detailing everything except, apparently, what happens at an execution," said Todd Scher, a death penalty lawyer from Miami Beach. "They log every visit, every phone call, every movement of an inmate under death warrant, but when it comes to the most important function a state does - taking a life - they don't have any record-keeping procedures."