Like every state that uses lethal injection to execute death-row prisoners, California was having difficulty last September obtaining sodium thiopental, a sedative used in most execution protocols.

Then, Arizona came to its aid, making a secret handoff of the drug that illustrates the paranoia and suspicion surrounding its importation. The mission was "very political and media-sensitive," one California prison official wrote to another, and needed to be carried out discreetly.

Arizona had obtained sodium thiopental from a pharmaceutical-supply house in London, and was refusing to divulge its sources, spurring speculation it had skirted drug laws.

In fact, FDA officials had signed off on the importation, even as a press officer in Washington, D.C., claimed that there were no approved means to import the drug.

California's search for the drug was as clandestine as Arizona's, and a series of e-mails obtained in early December by the American Civil Liberties Union from the California Department of Corrections and Rehabilitation read like a script from a 1960s episode of "Mission: Impossible."

"May have a secret and important mission for you," begins one e-mail written on the afternoon of Sept. 29, from that department's undersecretary to another official. He was searching for thiopental, even canvassing hospitals.

"So, out of the blue, I find some in AZ," he wrote. "I might need one of your So Cal guys to go to Florence, AZ and pick up a quantity of the drug and drive it to (San Quentin). . . . Could you handle something like this?"

The answer came back: "Absolutely. Give me the green light and it will be done very discreetly."

Arizona Department of Corrections Director Charles Ryan had authorized the transfer to California of 12 grams of its British thiopental.

Within hours, the plan was set and, according to e-mails, a pickup crew was in Florence by 9 a.m. Sept. 30. The team headed back to California, making a rendezvous with another team in Bakersfield that would drive the last leg to San Quentin.