The Drug Enforcement Administration took at least a decade to address known problems with a special unit linked to scores of civilian deaths in foreign countries, according a document obtained exclusively by VICE News.

The DEA’s “Sensitive Investigative Unit” or SIU has been the subject of intense scrutiny over the past year. The program allows the DEA to vet and train police and military personnel from other countries, then work closely with them to target drug kingpins and cartels. The DEA credits the SIU with producing some of its biggest busts, but the successes have been overshadowed by a series of deadly disasters.

A pair of investigative reports published jointly last year by ProPublica and National Geographic detailed how an intelligence leak from one SIU operation led to the massacre of at least 60 people by Los Zetas in Mexico in 2011, and poor operational security in another caused five innocent Mexicans to be kidnapped and disappeared by the cartel in 2010. Another DEA operation in Honduras in 2012 led to a shootout that killed four civilians.

Last week, in the wake of the revelations, four powerful Democratic members of Congress sent a letter to the Office of the Inspector General calling for the watchdog to investigate the SIU. But it appears that as recently as last summer, the DEA was still working to fix major issues the Inspector General flagged in 2007.

VICE News obtained via the Freedom of Information Act a heavily redacted version of the “Program Manual” that lays out the DEA’s standard operating procedures for the SIU. The document (see PDF below) includes a memo reauthorizing the program signed on August 29, 2017, by Anthony Williams, the DEA’s assistant administrator and chief of operations. The memo says the reauthorization “will address specific recommendations” from the Inspector General’s 2007 audit of the DEA’s international operations, including “several instances” of “lack of accountability and oversight.”

Three independent experts who reviewed the redacted Program Manual at the request of VICE News found the memo from Williams troubling, and said it’s possible that the deadly incidents in Mexico and Honduras could have been avoided had the DEA moved more quickly after the 2007 audit.

“You could have prevented these incidents or at least mitigated the impact that these operations have had in the region”

“Clearly, these concerns were raised well in the past,” said Maureen Meyer, director of the Mexico program at the Washington Office on Latin America. “You could have prevented these incidents or at least mitigated the impact that these operations have had in the region.”

The DEA declined to answer questions from VICE News about the SIU, including whether the agency is still in the process of implementing changes recommended by the 2007 audit. DEA spokeswoman Mary Brandenberger said in a statement that the SIU program “has proven to be an effective international program for supporting host nation counterdrug units capable of conducting international drug investigations.”

A spokesman for the Justice Department’s Office of the Inspector General declined to comment when asked whether an investigation into the DEA’s SIU program is in the works.

The DEA launched the SIU program in 1997 in Colombia and it has since expanded to 12 countries around the globe. The reauthorization memo signed by Williams says the SIU “has proven to be one of the most successful programs… with respect to dismantling major international drug trafficking organizations.”

The stated mission of the program is to “form well-trained foreign counterpart drug investigative and intelligence units of high moral character and integrity.” The DEA handpicks trusted soldiers and police officers for the units, and members must pass a lie detector test, background check, and drug screening, and receive special training at DEA headquarters in Quantico, Virginia. Once the units are formed, the manual says, they “work under the guidance and support of DEA.”

Mike Vigil, a retired DEA agent who served as the agency’s chief of international operations, told VICE News the idea behind the SIU is to “have the ability to pass sensitive information to an elite group” of foreign counterparts. But the problem, he said, has long been that the DEA isn’t permitted to vet the high-ranking officers who ultimately control the units.

“Members of the SIU, along with its commander went through the vetting process, but for example the Mexican government did not allow for anybody higher up in the chain of command to be vetted,” Vigil said. “Yet these individuals would be involved and have access to the information.”

The 2007 audit by the Office of the Inspector General “revealed significant deficiencies with the DEA’s management and oversight of its investigative activities within its vetted unit program.” The audit also identified “poor security practices,” though specifics were redacted in the public version of the report.

The SIU program in Mexico has been especially troubled. Since 2000, according to ProPublica, at least two SIU supervisors have been assassinated after their identities were leaked. Another SIU supervisor, Ivan Reyes Arzate, was indicted last year by U.S. authorities for selling information to drug traffickers. He has denied the charges.

Last June, ProPublica reporter Ginger Thompson revealed how a DEA agent persuaded a high-level Los Zetas member to hand over information that would allow authorities to track the movements of cartel leader Miguel Ángel Treviño and his brother Omar. Almost immediately after the DEA shared the information with its vetted allies in Mexico, the brothers got wind of what was happening. The Zetas responded by laying waste to the town of Allende, the home of the suspected snitches about 40 miles from the U.S. border. ProPublica confirmed that around 60 people were killed, but one estimate from a victims association put the death toll closer to 300.

VICE News reported on the Allende massacre in 2014, before the cause of the rampage was fully revealed. Witnesses said cartel members demolished homes using grenades and heavy equipment, leaving behind only piles of rubble. Townspeople said dozens of residents — including anyone even vaguely connected to the suspected betrayers — were rounded and murdered. The bodies were reportedly placed in drums of diesel fuel and incinerated.

In December, Thompson reported how Mexican federal police officers working with the SIU had checked into a Holiday Inn in the city of Monterrey as part of an undercover operation to capture another Los Zetas leader. Again, the cartel was tipped off about the operation. The DEA operatives fled the hotel, and when Zetas gunmen showed up looking for them they instead kidnapped four bystanders who vaguely fit their profile. The families of the kidnapping victims received ransom demands but they were never seen again. Only after ProPublica’s report did the families learn about the link between the DEA operation and the disappearances of their loved ones.

According to ProPublica, the SIU program manual was distributed for the first time in December — marking the first time in the 20-year history of the program that the DEA put the rules and procedures for its special international operation in writing. The copy obtained by VICE News indicates that some rules were not followed leading up to the kidnappings at the hotel in Monterrey.

The manual says the DEA is supposed to “remain involved” in leasing properties for SIU operations, to ensure the arrangement “is executed in such a way as to protect the security of the facility and the SIU members.” Another DEA memo from 2012 describes how the agency bent its rules to allow SIU operations to have easier access to cash, up to $50,000 at a time to be repaid within 90 days. But according to Thompson’s reporting, the SIU members in Monterrey “used personal credit cards to secure their rental cars and hotel rooms.”

Eric Olson, an expert on security issues and organized crime in Mexico at the Woodrow Wilson International Center for Scholars in Washington, DC, said after reviewing the SIU manual for VICE News that the Monterey operation posed an obvious security risk.

“It should be evident there are serious risks here even in the best of circumstances,” Olson said. “Common sense would say you don’t want to do this in a public place. I don't know why they did it. It just doesn’t make any sense to me.”

Olson called the DEA’s apparent failure to immediately act on the recommendations from Inspector General’s 2007 audit “deeply disappointing.”

The Inspector General also scrutinized the DEA last year over the 2012 incident in Honduras. In that case, a joint DEA-Honduran team on a late-night anti-drug operation opened fire on a boat carrying suspected drug traffickers after claiming to have come under fire. One man, two women, and a 14-year-old boy were killed. Video footage released later contradicted the DEA’s version of events, and the Inspector General found that the DEA “provided inaccurate and incomplete information to DOJ leadership and Congress.”

Olson said that by providing misleading information and attempting to cover-up its mistakes in Honduras, the DEA set a poor example that ran contrary to the mission of the SIU program, which is intended provide a model for other nations’ law enforcement to follow.

“It’s not for lack of structure and rules and procedures and good intentions,” he said. “It’s just that when you’re in the field and operating, shit happens. I’m sorry to say it, but things happen. If you don’t have mechanisms for accountability and oversight, then you're in a situation where there’s impunity.”

The recent letter to the Office of the Inspector General from Congress, signed by Sen. Dianne Feinstein, Sen. Patrick Leahy, Rep. Eliot Engel, and Rep. Jerrold Nadler — the ranking Democratic members of key committees tasked with DEA oversight in the House and Senate — specifically referenced the incidents in Mexico in calling for “a thorough investigation into the practices of the DEA’s vetted units.”

In a statement to VICE News, Engel, the ranking Democrat of the House Committee on Foreign Affairs, said that “moving forward, I will demand greater accountability and transparency about the activities of these units.”

“U.S. law enforcement operating abroad must be held to the highest standards,” Engel said. “I urge the DEA to immediately implement reforms to their vetted units programs that the Justice Department’s Inspector General prescribed. At the same time, Congress needs to be kept much better informed of the specific operations carried out by U.S. vetted units in Mexico and throughout the world.”

“We did stop a lot of the information getting comprised, not entirely, not 100 percent, but then again in any type of operation you're never going to have 100 percent”

Vigil, the retired DEA agent, defended the SIU, arguing that despite the leaks the program is better than the alternative, which would be having no vetted units at all. He said the DEA has made “made numerous efforts” and “great strides” in terms of adding oversight and accountability. He also said the SIU has made it easier for the DEA to keep secrets abroad.

“It minimized the compromise of information,” said Vigil, who wrote a book about his time at the DEA and is now an expert at The Cipher Brief. “Were there still issues involving corruption? Yes. But at least it was not compromise wholesale as it once was. We did stop a lot of the information getting comprised, not entirely, not 100 percent, but then again in any type of operation you're never going to have 100 percent.”

The problems with the program in Mexico, however, will continue to remain in the spotlight. Last week, family members of victims of the Allende massacre visited Washington, D.C. and spoke on a panel about the drug war. Audible has also produced a five-part podcast series about the incident based off Thompson’s reporting.

Experts also warned that history could repeat itself if the DEA continues to trust foreign law enforcement agencies with sensitive secrets. Sanho Tree, director of the Drug Policy Project at the Institute for Policy Studies, said as long as the DEA is unable to vet high-ranking officers and government officials in Mexico and elsewhere, the possibility for leaks — and the deadly consequences that come with them — remain.