"We're not calling this euthanasia. We're not calling this mercy killings. This is second-degree murder," said Kris Wartelle, a spokeswoman for Attorney General Charles C. Foti.
The arrest warrants say Dr. Anna Pou and the two nurses intentionally killed four patients at Memorial Medical Center "by administering or causing to be administered lethal doses of morphine sulphate and midazolam."
Specifically, investigators say, the three accused killed four elderly
patients with lethal doses of the morphine and a sedative known as Versed, CBS News' Teri Okita reports.
"When you use both these drugs together it becomes a lethal cocktail
that guarantees they are going to die," Foti said.
In an affidavit, an agent for the Louisiana Justice Department wrote that Pou told a nurse executive three days after the hurricane hit that "lethal doses" would be administered to those patients who could not be evacuated.
"'Lethal doses of what?'" the nurse executive asked, according to the affidavit says. It says Pou answered: "morphine and ativan."
Two months after the hurricane, the attorney general subpoenaed more than 70 people in an investigation into rumors that medical personnel at Memorial Medical Center had euthanized patients who were in pain after the hurricane as they waited in miserable conditions for rescue. Foti has said previously that Louisiana law prohibits mercy killings of any sort.
Pou's attorney, Rick Simmons, said his client is innocent of any criminal behavior, and her mother said she was distressed by her daughter's arrest.
"Medicine was the most important thing in her life and I know she never ever did anything deliberately to hurt anyone," Jeanette Pou said in a telephone interview.
Memorial Medical Center had been cut off by flooding after the Aug. 29 hurricane swamped New Orleans. Power was out in the 317-bed hospital and the temperatures inside rose over 100 degrees as the staff tried to tend to patients who waited four days to be evacuated.
At least 34 patients died there during that period, 10 of them patients of the hospital's owner Dallas-based Tenet Healthcare Corp. and 24 patients in a facility run by LifeCare Holdings Inc., a separate company.
After the bodies were recovered, Orleans Parish coroner Frank Minyard said they were so decomposed the deaths could only be listed as "Katrina-related."
He later said samples had been taken from dozens of patients who died at various hospitals and nursing homes to test for potentially lethal doses of drugs such as morphine.