Aladar Vidak, 81, died in what were initially thought to be natural circumstances in August 2012 at the Jindalee nursing home in Narrabundah, a facility that has been the focus of two other death probes since 2007.

But tests soon revealed Mr Vidak's body contained alcohol at a concentration of roughly five times the legal driving limit.

Evidence suggests the alcohol may have been a contributing cause in the elderly man's death, along with other underlying medical conditions.

The detection of such high levels of alcohol raised alarm bells for authorities.

Mr Vidak did not drink and is not thought to have touched alcohol in three decades.

A coronial inquest into the death is on hold to allow police more time to try to determine exactly how the alcohol got into Mr Vidak's system.

Johnson Village Services, the company behind Jindalee, has emphatically stated its staff did nothing wrong, saying they did not give alcohol to the elderly resident before his death.

Alcohol is kept at the facility, but only under lock and key, and not on the "a-wing", where Mr Vidak was residing.

Wine and beer is allowed at meal time, and families and residents can bring in small amounts of alcohol, as long as it does not adversely impact on residents or staff.

There is also a happy hour held once every week in Jindalee's "bush lounge", but it is strictly supervised by staff, according to Johnson Village Services.

Managing director Gary Johnson said the coroner, in interim findings, found there was no evidence of wrongdoing by Jindalee or its staff.

"We concur with the coroner's findings that our staff did not administer any alcohol to him, that there was no alcohol on that wing, that alcohol that is in the facility is kept under lock and key and supervision is reasonably tight."

"Mr Vidak, to the best of our knowledge, did not drink alcohol at all."

No final findings have been made by the coroner.

Police have declined to comment in detail on the case, simply confirming it was referred to them. Asked if they were investigating whether staff had given Mr Vidak alcohol, ACT Policing said it was investigating "all the circumstances" surrounding the death.

Mr Johnson said the police investigation was not unreasonable, saying most people would acknowledge there was an unexplained circumstance behind Mr Vidak's death.

"Nobody has been able to adequately explain the tests that were carried out on Mr Vidak after he passed away," he said.

He said his staff were highly experienced and professional. "We are at a loss to explain it," he said.

The coronial process will resume at some stage in the future, although no further date has been set.

Two previous deaths have occurred at Jindalee in suspicious circumstances. In January 2007, Ruth Rankin Gibson Mussen was pulled from her bed in the dementia ward at Jindalee. The frail 94-year-old later died from a broken femur and multiple organ failure. That prompted calls from the coroner for CCTV cameras to be installed in the dementia ward, something Jindalee rejected.

In 2012, resident Charles McCulloch, also 94, died in suspicious circumstances at the same dementia ward. He was found with facial injuries after a disturbance in the 32-bed ward.

The inquest into that death is still before the courts.

Both deaths were investigated by federal authorities under the Aged Care Complaints Scheme, and Mr Johnson said Jindalee was cleared of any wrongdoing.

The Department of Social Services, the department responsible for such investigations, declined to comment on past probes of Jindalee.