Agents with the Drug Enforcement Administration wrote their own rules for a secret informant program that gave broad leeway to DEA sources as they bought and sold illicit drugs.
DEA officials then attempted to block a probe of its confidential sources program by the Justice Department inspector general, according to a report made public Tuesday.
The Justice Department watchdog said its probe was stalled "for months at a time" when DEA officials blocked access to their files.
"Our audit work thus far has been seriously delayed by numerous instances of uncooperativeness from the DEA," the inspector general wrote.
Although the inspector general set out to conduct a thorough review of the DEA's confidential source program in February of last year, the watchdog has since managed only "limited" success.
The audit, which was sparked by multiple allegations of wrongdoing in the program, is not yet finished and will eventually expand to other areas of the program DEA officials called the "bread and butter" of their agency.
Michael Horowitz, the Justice Department's inspector general, said some of the risks involved in the informant program include the fact that "these individuals often have criminal backgrounds" and that they cooperate with DEA investigations "in return for cash or consideration for a reduced criminal sentence."
"Confidential sources are sometimes authorized to engage in activity that would be illegal if they were not acting under the direction of the federal government," Horowitz said in a podcast Tuesday.
He used the example of the DEA allowing a confidential source to buy and sell drugs in order to track down the leader of a drug ring to illustrate the risks associated with the practice.
Such informants may interpret their limited authority to break the law for investigative purposes as a green light for additional illegal activity for which they actually have no immunity, the report said.
What's more, DEA officials selected which elements of the attorney general's guidelines for informants they were going to incorporate into their own policy, ignoring others.
The DEA relied on more than 240 confidential informants with little regard to the consequences of doing so.
Officials allowed long stretches of time to pass during which no review was performed, creating "a significant risk that improper relationships between government handlers and sources could be allowed to continue over many years," the report said.
Horowitz highlighted the drug agency's lack of supervision of its own informants.
"We found that from 2003 to 2012, the DEA committee charged with reviewing these long-term sources considered each source for an average of just 1 minute each. And that's when there was any review at all," he noted.
In that nine-year period, officials met just seven times to discuss the continued use of their informants in the field.
The inspector general's team attempted to observe one such meeting in the summer of 2014, but faced significant resistance from DEA officials.
After the drug agency postponed the meeting multiple times, the watchdog was allowed to observe only a portion of the meeting, during which it became clear to the auditors that the DEA had used the intervening days to prepare the required paperwork.
"Therefore, had the meeting occurred as scheduled," the agency officials "would not have had the benefit of up-to-date status information ... or updated criminal history checks," the report said.
The program was made up of far more than informants already embedded in the world of illegal drugs, however.
Confidential sources included doctors, lawyers and journalists whose participation in DEA intelligence-gathering efforts fell outside of the attorney general's guidelines.
Between 2013 and 2014 alone, the DEA paid more than $1 million in workers' compensation benefits to informants or their dependents for sources who had been hurt or killed on the job.
The drug agency had no policies in place to govern the payment of such benefits, allowing some informants to continue collecting their paychecks while simultaneously receiving the disability benefits.