NEW YORK (NYTIMES) - In an interview room at Tullamarine Airport in Melbourne, an Australian immigration officer sat down across from tennis star Novak Djokovic.

The officer started with a warning.

"I am now going to caution you," the officer said, according to a public transcript both sides have agreed is accurate, "that if you provide false or forged documents or false or misleading information you can be prosecuted under Australian laws."

Even before his plane touched down in Melbourne on Wednesday (Jan 5), Djokovic's application for a visa to play in next week's Australian Open was under scrutiny, and questions swirled about whether he would be allowed into the country. The answer, at least initially, was no.

Australia, which requires all foreign visitors to be vaccinated but grants exemptions in limited cases, cancelled the tennis world No. 1's visa after his airport interview, only to have a judge reinstate it on Monday on procedural grounds.

"This is his greatest victory, greater than all the Grand Slams that he has won," his mother, Dijana, said at a news conference on Monday in Belgrade, Serbia.

Now, as Australia's top immigration official Alex Hawke considers rejecting Djokovic's visa again and its Prime Minister Scott Morrison calculates the political cost of the fight, published reports and Djokovic's own social media posts have raised questions about the validity of his visa paperwork and his actions in the days around Dec 16, when, by his own account, he learnt that he had tested positive for the coronavirus.

Cloud over test result

To obtain a visa to enter Australia, the Serb and his lawyers submitted documents that said he had tested positive for the coronavirus on Dec 16. He cited that positive result when he was interviewed by Australia Border Force officials upon his arrival in Melbourne.

He produced the Dec 16 test result "unprompted," the Australians said in a court filing.

The filing also includes the timing of the test, which was collected at about 1pm on Dec 16, and of a positive result returned seven hours later.

But the positive test result, which is at the heart of the medical exemption that he needed to obtain to play in the Australian Open, has been cast into doubt by a published report.

On Monday, the German newspaper Der Spiegel reported that it had scanned the unique computer code attached to Djokovic's test result - which was included in court filings related to his visa appeal - and found that it initially reported the test was negative for the virus.

But just over an hour later, when Der Spiegel journalists and others checked the code again, the linked webpage said Djokovic's test was positive. That was still the case on Tuesday morning.

Djokovic's agent and spokesman did not immediately respond to a request for comment on Tuesday.

A public figure, in public

The confusion about his test result, though, only renewed questions about his actions on the day of the test and the week that followed.

If he had tested positive for Covid-19 on Dec 16, then his actions in the ensuing days - when he should have been isolating - could have endangered the health and safety of dozens of people.

On Dec 16, the day that Djokovic sought a test for the virus, he was honoured with a stamp by the Serbian postal service and toured its facility. In photos from the event, he appears with the acting director of Serbia's postal service, Zoran Dordevic.

Neither Djokovic nor Dordevic is masked in a photo, or in other pictures from the event.

Djokovic also took part in an hour-long panel discussion that day at a tennis centre that bears his name.

The topic? "The role and establishment of authority in the development of character and discipline."

In a video of the event posted on YouTube, neither Djokovic nor any of the other panellists wears a mask.

A day later, the player reportedly appeared at an event to honour youth tennis players at the tennis centre that bears his name. None of the dozens of people in a group photo from the ceremony, including Djokovic, whose positive test result was confirmed a night earlier, wore a mask.

The next day, Dec 18, Djokovic took part in a photo shoot with the French sports publication L'Equipe. The newspaper has published the photos repeatedly in its coverage of his visa dispute.

Serbia's prime minister, Ana Brnabic, told Reuters in an interview on Tuesday that if Djokovic attended events after learning he was positive, that he would have "clearly violated the rules".

What now?

Djokovic, who confirmed in his airport interview that he is unvaccinated, has said little publicly beyond two Instagram posts thanking his supporters. He was "pleased and grateful" about the judge's ruling, he said on Monday, and clearly planning to stay in Australia, where he is scheduled to begin the defence of his Australian Open title next week. He is already practising.

Australia's Immigration Minister Hawke, meanwhile, continues to "thoroughly consider the matter" of expelling him, according to his spokesman.

One thing government officials will weigh is if Djokovic was truthful in his statements and declarations.

As the officer noted in his first airport interview, providing false or misleading information could be deemed a crime in Australia. Losing his visa again could result in the Serb being barred from returning to Australia - and to the tennis season's first major tournament - for at least three years.

At the news conference in Serbia, Djokovic's brother Djordje spoke repeatedly about the transparency of the process that had vindicated his brother, declaring that "truth and justice came to the light".

But when he was confronted with the contradictions in the timing of Djokovic's positive test result and his multiple public appearances that week, Djordje Djokovic abruptly ended the questioning.

"OK, so, uh, this press conference is adjourned," he said.