Federal investigators are refusing to release details of a criminal probe into a disaster the Environmental Protection Agency (EPA) caused two years ago, The Daily Caller News Foundation Investigative Group has found.

The EPA’s Inspector General (IG) provided the Department of Justice evidence that an employee involved in the August 2015 Gold King Mine disaster violated the Clean Water Act and made false statements. The Justice Department declined to prosecute him, the IG announced in October 2016.

The watchdog wrote a report on its completed investigation but is now keeping it secret.

“The material you requested … are part of one or more open law enforcement files,” EPA IG associate counsel Susan Barvenik told TheDCNF in a letter. Producing “such records could reasonably be expected to interfere with ongoing enforcement proceedings.”

An EPA spokeswoman provided conflicting information about the probe.

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“Investigative activity has ended, but the investigation is still administratively open,” IG spokeswoman Tia Elbaum told TheDCNF. “We haven’t closed the investigation as further actions could still be pursued. We do not have plans to release the records at this time.”

She added that the IG won’t close the probe until the EPA decides if it will punish the referred employee. Saturday will mark two years since the disaster that spurred the investigation. (RELATED: EPA’s Gold King Mine Boss Dodged Federal Probe By Retiring)

The IG launched the probe after an EPA crew breached Colorado’s Gold King Mine in August 2015, which unleashed a three-million-gallon flood of toxic waste into drinking water for three states and the Navajo Nation. No one was punished for the incident, and numerous government reports omitted crucial details.

The IG’s letter was a response to TheDCNF’s Freedom of Information Act request for the watchdog’s report. TheDCNF also sought any administrative action the EPA took as a result of the probe, but there’s no evidence anything was done.

“After a thorough search based on the information you provided, the Office of Inspector General has determined that we have no records that are responsive to … your request,” Barvenik’s letter said.

“This does not mean that the agency is not pursuing administrative actions,” Elbaum added.

But it does confirm that the EPA still hasn’t punished the employee the IG said lied during the investigation. (RELATED:Watchdog Relied On Someone It Called A Liar To Clear EPA Of Wrongdoing)

Similarly, the IG cleared the agency of any wrongdoing surrounding the disaster in a June audit and provided no recommendations for improvement. (RELATED: EPA Cleared In Agency-Caused Environmental Disaster, Despite Official’s Admissions)

Meanwhile, the House Committee on Natural Resources released a thorough report less than seven months after the disaster, which detailed the EPA’s mistakes and other questionable details.

TheDCNF has also published numerous investigations revealing contradictions in the EPA’s explanation of the events surrounding the spill and other facts that suggest the agency engaged in a cover-up to obscure wrongdoing.

The EPA, for example, selected an agency with multiple interests in the Gold King Mine site to conduct what was called an “independent” review of the incident.

Additionally, the IG’s June audit relied on official statements and made no attempt to discredit or invalidate uncovered, contradicting details. The watchdog, for example, reasserts the EPA’s claim that breaching Gold King Mine was an accident, even though internal emails shows it was intentional and in violation of written orders.

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