A deer killed by federal sharpshooters in a chronic wasting disease “hot zone” in southeastern Minnesota had holes and cuts on its ears indicating it may have escaped or been released from a captive deer farm, sources at the state Department of Natural Resources (DNR) said Thursday.

The discovery, made recently when the animal was shot during a culling operation to reduce chances the disease will spread to other whitetails, is under investigation by DNR conservation officers and wildlife biologists as the agency tries to explain the origin of the state’s largest-ever outbreak of CWD in wild deer.

Tissue from the mysterious deer did not test positive for CWD, but the presence of a suspected farmed deer mingling with wild deer in the core of the outbreak area near Preston, Minn., is both intriguing and frustrating to wildlife officials and deer hunters. Both groups recently have expressed dismay over an alleged cozy relationship between Minnesota’s commercial deer industry and its regulator, the state Board of Animal Health.

In an e-mail Wednesday to legislators, DNR Fish and Wildlife Division Director Jim Leach provided an overall update on CWD surveillance, including the finding of what “appears to be a formerly ear-tagged deer.” Leach noted that the Board of Animal Health was notified and “we have asked for their cooperation in tracing this deer’s origin.”

Paul Anderson, who heads the farmed deer program at the Board of Animal Health, said Thursday he saw the DNR’s photographs of the ear holes and cuts. “I don’t know exactly what to think of that,” he said.

Anderson said the board is not aware of any escaped deer in the area.

Lou Cornicelli, the DNR’s top big-game researcher, said Thursday the agency isn’t “pointing fingers” and continues to investigate three separate possible causes of the outbreak. One idea is that a CWD-infected deer wandered in from Wisconsin or Iowa. Another theory is that the infectious carcass of a CWD-infected deer shot in another state was brought to Minnesota and dumped in the woods.

Cornicelli said the possible ear-tagged deer is being investigated under the third scenario: Farmed deer may have escaped or were released into the wild, carrying CWD with them. Since 2002, there have been seven CWD outbreaks on Minnesota deer farms. The only previous CWD outbreak affecting wild deer in Minnesota happened in 2011, when a single whitetail was infected near a CWD-ridden elk farm in Pine Island.

State conservation officers have been asking Preston area residents for tips about the suspicious deer’s origin, and Cornicelli said he also is urging anyone with information to come forward. By law, escaped captive deer must be reported to the Board of Animal Health if they are out of their pen for more than 24 hours. Yearly farm audits by the board are supposed to account for any escapes.

Cornicelli said the DNR will do genetic work on all 10 of the CWD-positive deer found in the hot zone, which he described as being as small as a “pin prick on a map.” An 11th infected deer was found about 5 miles north of the cluster. They were all shot by hunters or sharpshooters over the past three months.

The previously ear-tagged deer was taken in the core area near Preston. It had holes and notches in both ears, the DNR said. Earlier in the CWD surveillance regime, a buck was harvested 7 miles south of the CWD core. On Thursday, the DNR said in a memo that the animal had “suspicious tears with possible holes in both ears.” However, the memo said, “we could not conclusively determine if these were ear tag marks.”

Cornicelli said both animals with marked ears will be tested for genetic information. If their DNA is different from that of local deer, that information would add to suspicions that they possibly came from captive herds.

Two deer hunter organizations, including the Minnesota Deer Hunters Association, have recently requested a state audit of the farmed deer program. Those requests came after Cornicelli and DNR Wildlife Health Program Supervisor Michelle Carstensen openly questioned the board’s effectiveness. They fear that infected farmed deer will escape and spread disease to Minnesota’s wild herd — a population that stimulates $500 million a year in hunting-related activities and cherished family gatherings.

“I struggle with the closeness of the regulators and the industry,” Cornicelli told the Star Tribune in a story published in February.

Anderson declined to comment on calls for an audit of his program. He said in February that the Board of Animal Health is keenly focused on CWD prevention and mindful that transmission of the disease can travel in or out of the mandatory 8-foot fences that enclose private herds.

Dr. Beth Thompson, the state veterinarian, said the board will accept whatever decision is made about an audit.

Minnesota is home to 460 deer and elk farms that generate rural jobs and economic activity last measured in 2011 at $17.6 million a year.