An Argentine police officer shows a package of cocaine found on the premises of the Russian Embassy in Buenos Aires.
Moscow CNN  — 

A massive cross-border drug bust has become a major public relations nightmare for Russia’s diplomatic service, turning a positive story of international police cooperation into a snowballing media scandal at home.

Last week, Argentine police announced the drug bust: The country’s Gendarmería Nacional said police had discovered and seized 389 kilograms of cocaine – more than 850 pounds – on the grounds of the Russian Embassy in Buenos Aires in December 2016.

A police officer opens up a package of the seized cocaine on December 14, 2016.

A sting operation followed, with Argentine and Russian investigators replacing the drugs with flour and then fitting the bags with GPS tracking devices to monitor the shipment, and identify and apprehend the smugglers.

It seemed to have been a textbook example of cross-border cooperation, with Russian diplomats tipping off the Argentinians about the drugs, and the two countries working together to stop illicit drug traffic. Now it’s a story the Russian government appears to want to wish away.

In recent days, Russian media have begun raising uncomfortable questions for the Russian Foreign Ministry, questioning official explanations.

The basic facts are not in doubt: Investigators said a former employee of the Russian Embassy in Argentina was among those arrested at his home in Russia. Maria Zakharova, the Russian Foreign Ministry spokeswoman, confirmed that a member of the “technical staff” of the embassy who had worked on a short-term contract had been involved, and that the drugs had been discovered on the premises of a school on the embassy grounds.

A police officer guards the suitcases found carrying the drugs.

First, there were questions about how, exactly, the massive drug shipment could end up in a closely guarded diplomatic compound. Maxim Mironov, a professor and blogger whose children study in the school, said he believed the explanation was a “a lie.”

The school grounds, Mironov said, are “constantly guarded by FSB officers” – members of the Federal Security Service, one of Russia’s intelligence agencies.

“Parents’ entrance to the school grounds is strictly prohibited,” he wrote in a blog post. “If I need to talk to a teacher, they call her, she goes down and we talk at the entrance. If you need to meet with the principal’s office, then they escort me to the principal’s office.”

Then there were questions about how the shipment got to Russia. The Argentinian police released photos and videos of the sting operation that included shots of the plane that transported the cargo back to Russia: an Ilyushin-96 with the tail number RA-96023.

That aircraft is part of the Special Flight Detachment Rossiya, a fleet of Russian government planes that ferries VIPs around the globe. That prompted intense speculation in the Russian media about how, exactly, a plane that belongs to the rough equivalent of the US presidential aircraft fleet was used for staging a drug delivery.

Argentine police released photos of the Russian plane involved.

The respected Russian business newspaper RBC, for instance, ran a major story about the role of the government transport aircraft in the cocaine trafficking case, drawing in part upon a Russian plane-spotting website,

The Russian Foreign Ministry denied the plane was involved, and the plane-spotting website was taken offline, but the story of the drug bust nonetheless began to turn into a media frenzy, with Russian news outlets publishing dozens of stories on the strange circumstances of the case and tracing the whereabouts of the plane. According to the website, the plane landed Monday in Bangkok, possibly carrying Russian National Security Council head Nikolai Patrushev, observers speculated.

Russia’s diplomatic service, which routinely lambasts foreign media for spreading anti-Russian propaganda, responded swiftly and vociferously to domestic coverage of the scandal.

On Tuesday, the Foreign Ministry said Russian media outlets covering the story had engaged in a “campaign replete with unverified and conspiracy information.” And they posted screenshots of those stories, emblazoned with a red stamp reading “FAKE” – an honor usually reserved for foreign news agencies that incur the displeasure of the ministry.

Zakharova, an official with a knack for soundbites and a combative social media style, turned her verbal firepower on those questioning the veracity of the official Russian account. Responding to suggestions the case “cast a shadow” on Russia’s diplomatic corps, she said: “It’s exactly the opposite. The success of this operation was ensured by the effective actions of the Russian ambassador and diplomatic personnel.”

And the Foreign Ministry also released a statement questioning the patriotism of Mironov, the man whose children attend the diplomatic school. The Russian Embassy in Buenos Aires released a scathing denunciation of him, saying “Mr. Mironov’s performance once again demonstrates his desire to make a name for himself by spitting on our country and its foreign policy service.”

An image release by the Argentine police of the drug haul.

The statement went on to insinuate that his children might be expelled from the school. “His children, we hope, will continue to study in the school at the embassy. Perhaps it will compensate them for the flaws of the anti-Russian atmosphere that reigns in their family.”

The Kremlin’s take on the mystery plane? Kremlin spokesman Dmitry Peskov swatted away questions Wednesday in a conference call with reporters.

Asked if Patrushev was on the plane, he said: “I do not have this information. I think it is necessary to refer these questions to the air company.”

And asked if he was keeping an eye on the burgeoning scandal, Peskov said: “This is not our prerogative. The Ministry of Foreign Affairs (should comment on that) and, as far as I know, they provided all the necessary information.”