Two weeks ago, Gov. Jay Nixon instructed the Missouri Department of Corrections to come up with a new procedure for carrying out lethal injections.

On Tuesday, the department announced that it had chosen a new execution drug: pentobarbital. But the state also made a change that will end up making it harder, if not impossible, to know where the drugs come from.

It was already illegal to reveal the identity of anyone who is – or ever was – a member of the state’s “execution team.” Previously, that team was limited to medical personnel and employees of the Department of Corrections directly involved in carrying out the execution.

But on Tuesday, the state expanded the definition of “execution team” to include the suppliers of execution drugs.

The change comes following reporting by St. Louis Public Radio that the state obtained its previous execution drug from a supplier who wasn’t authorized to sell it. What’s more, our reporting shows that both the supplier and the state were well aware that they were violating the manufacturer’s wishes.

This information became available through an open records request by the American Civil Liberties Union of Missouri. But under the new protocol, reporting like this would be illegal.

Missouri ACLU legal director Tony Rothert said the state changed the rules because it looked bad for buying drugs from an unauthorized distributor.

“The whole purpose of that statute is to silence the debate, and to prevent other members of the public from asking questions about how executions are done in Missouri,” Rothert said.

On Wednesday, the ACLU sued the state, arguing that the new protocol violates the First Amendment.

“It would be preferable if Missouri was open and transparent about what it’s doing as far as procuring drugs to execute people with,” Rothert said. “But if they’re not going to be open and transparent we’re going to do everything we can to force them to be.”

The ACLU previously had the open records posted on their website. After Tuesday’s protocol change, the organization took the documents down.

After consulting with our legal team, St. Louis Public Radio has decided to keep our story up. The Governor’s office, the Department of Corrections and the supplier have not disputed any of the facts in our reporting.

The ACLU is hoping the courts will act quickly on their lawsuit.

“With an execution still scheduled for the end of November, we certainly think this is urgent that we again have access to this crucial public information, and make it available,” Rothert said.

The Governor’s office and the Department of Corrections have both failed to respond to our request for comment.

Update 10/24/13

When asked at a press conference about the rule change, Nixon stood by the Department of Corrections, but said that he didn't tell them to make the change.

“It’s better to talk to Corrections the process there," Nixon said. "All I did was say was, because of propofol (the previous drug) we’re not going to move forward there, so establish a new protocol. It's better to talk to Corrections about the process there.”

The Mo. Department of Corrections has still not responded to our request for comment.

Follow Chris McDaniel on Twitter: @csmcdaniel

Follow Veronique LaCapra on Twitter: @KWMUScience