Doctors at the U.S. Department of Veterans Affairs medical center in Tomah, Wisconsin, engaged in unsafe clinical practices while the hospital leadership created a culture of fear that compromised care and harmed the staff, according to a preliminary report released today.

The report, written by the VA’s interim undersecretary for health, Carolyn Clancy, is based on an internal probe the agency announced in January after The Center for Investigative Reporting revealed that runaway opiate prescriptions had caused some veterans to call the hospital “Candy Land.”

Last August, a 35-year-old Marine Corps veteran died of an overdose while in the hospital’s psychiatric ward.

The VA’s internal investigation confirmed many of CIR’s findings. It found that Tomah VA patients were 2.5 times more likely than the national average to be prescribed heavy doses of opiates, and that narcotic painkillers frequently were issued in combination with tranquilizers – a combination that can cause a person to stop breathing.

The preliminary report describes multiple instances of “patient harm at least partially attributable to prescribing practices” at the hospital and says that veterans’ medications were not changed even “in the face of aberrant behavior.”

Clancy said the investigation would continue. Tomah VA chief of staff David Houlihan, whom veterans nicknamed the “Candy Man,” has been placed on administrative leave while the VA’s internal investigation continues, as has Deborah Frasher, a nurse practitioner who worked closely with Houlihan.

In addition to the agency’s internal review, the Tomah hospital also is being investigated by the VA’s inspector general, two congressional committees and the Drug Enforcement Administration, while the Wisconsin Department of Safety and Professional Services has opened an inquiry into Houlihan, Frasher and pharmacist Margaret Hyde at the Tomah VA, which could cause them to lose their medical licenses.

Aaron Glantz was a senior reporter at Reveal. He is the author of "Homewreckers: How a Gang of Wall Street Kingpins, Hedge Fund Magnates, Crooked Banks, and Vulture Capitalists Suckered Millions Out of Their Homes and Demolished the American Dream." Glantz produces journalism with impact. His work has sparked more than a dozen congressional hearings, numerous laws and criminal probes by the Drug Enforcement Administration, FBI, Pentagon and Federal Trade Commission. A two-time Peabody Award winner, finalist for the Pulitzer Prize, multiple Emmy Award nominee and former John S. Knight journalism fellow at Stanford University, Glantz has had his work has appear in The New York Times, Chicago Tribune, NBC Nightly News, Good Morning America and PBS NewsHour. His previous books include "The War Comes Home" and "How America Lost Iraq."