Texas prison officials don’t have to tell the public where they get execution drugs, Attorney General Greg Abbott said Thursday, reversing himself on an issue being challenged in several death penalty states.Since 2010, Abbott, the Republican nominee for governor in the nation’s busiest death penalty state, had three times told prison officials that they should reveal the source of the drugs. He ruled that the benefits of government transparency outweighed the state’s objections. But on Thursday, Abbott’s office sided with state prison officials who said their supplier would be in danger if identified, citing a “threat assessment” signed by Texas Department of Public Safety Director Steven McCraw. The assessment, a one-page letter dated March 7, said pharmacies “by design are easily accessible to the public and present a soft target to violent attacks.” Naming a pharmacy that supplies execution drugs “presents a substantial threat of physical harm … and should be avoided to the greatest extent possible,” the letter said. Abbott’s decision, which can be appealed to the courts, came the same day that Missouri Attorney General Chris Koster said his state should consider creating its own laboratory for execution drugs rather than relying on “uneasy cooperation” with outside sources. A state-run lab would be a first, and it wasn’t clear whether Missouri could implement the change without approval from the Legislature. Lawyers for Death Row inmates say they need information about the source of the drugs to verify their potency and to protect inmates from unconstitutionally cruel and unusual punishment. Courts — including the U.S. Supreme Court — have yet to halt an execution based on a state’s refusal to reveal its supplier. Unlike in some states, Texas law doesn’t specifically say whether prison officials must disclose where they buy lethal-injection drugs. Abbott’s opinion cites the threat assessment as the justification for doing so, saying that “in this instance and when analyzing the probability of harm, this office must defer to the representations of DPS, the law enforcement experts charged with assessing threats to public safety.” State prison officials have provided little public evidence to support their assertion that the supplier would be in danger.State and local law enforcement officials, including a spokesman for the Department of Public Safety, said last month that they were not investigating any threats against a Houston-area compounding pharmacy previously identified as the supplier. The pharmacy’s owner had complained of “constant inquiries from the press, the hate mail and messages,” and the DPS assessment released Thursday said some of the threats “should be taken seriously.” It does not say why, and an agency spokesman did not respond to a message Thursday night asking whether those threats are now under investigation. In Missouri, Koster said he believes that his Legislature “should remove market-driven participants and pressures from the system and appropriate funds to establish a state-operated, DEA-licensed laboratory to produce the execution chemicals in our state,” according to a transcript provided by his office.“As a matter of policy, Missouri should not be reliant on merchants whose identities must be shielded from public view or who can exercise unacceptable leverage over this profound state act,” Koster said. This month, The Associated Press and four other news organizations sued the Missouri Department of Corrections, saying the state’s refusal to provide information on the execution drug violates the public’s constitutional right to have access to information about the punishment.Death penalty states have been scrambling to find new sources of drugs after several makers, including many in Europe, refused to sell drugs for use in lethal injections. Several states have turned to compounding pharmacies, which are not as heavily regulated by the Food and Drug Administration. Abbott’s latest decision stems from an open-records request filed ahead of the executions of Tommy Lynn Sells and Ramiro Hernandez-Llanas. Texas prison officials were using a new batch of pentobarbital, a powerful sedative, but they refused to name the supplier. The inmates’ attorneys said that violated the prisoners’ rights and asked Abbott to step in. They made similar arguments in court, but those appeals were turned down. Abbott’s decision is expected to be appealed and could land in the Texas Supreme Court. Prominent defense attorney Maurie Levin called Abbott’s decision “deeply disturbing and frankly quite shocking.” “Serious questions surround this about-face, including why our attorney general, who once championed transparency, is suddenly now supporting secretive government practices,” Levin said in a statement. Associated Press writer Jim Salter in St. Louis contributed to this report.