August 8 started like any other day in the tiny northern Russian town of Nyonoksa — but in the early hours, the first of two explosions sounded. At 9am, the second enormous blast went off, killing seven people and putting countless more in danger.
The explosion at the town's weapons testing range killed up to seven and released a cloud of gas over a nearby town.
A radiological alert was issued to residents, but adjacent sensors belonging to an international network of nuclear monitoring devices suddenly went silent.
Intelligence officials believe the explosion came from a prototype SSC-X-9 "Skyfall" nuclear-powered cruise missile, called 9M730 "Buresvestnik" (Petrel) by Russia.
Now, analysis of the fallout from the explosion suggests a nuclear reactor blew up. But Moscow is continuing its attempts to sow confusion around the disaster.
Russia's Defence Ministry declared background radiation remained normal. But the state weather agency said radiation levels had spiked.
Russia's state nuclear agency, Rosatom, admitted on August 10 the accident involved "isotope power sources" but gave no further details. Russia's weather agency has finally confirmed the blast ejected radioactive material into the air.
But Moscow continues its efforts to clampdown on claims of nuclear contamination.
While reports immediately after the accident suggested contamination was too low to pose any danger, the Kremlin's ongoing lack of transparency is raising fresh fears.
A doctor who treated survivors of the mysterious accident has reportedly been found to be contaminated with caesium-137, a radioactive isotope that is commonly found in the wake of nuclear fission.
Medical staff reportedly responded to victims of the accident wearing nothing more than face masks for protection.
But Moscow insists the caesium-137 since found in one doctor's body must have come from "Fukushima crabs".
Russian investigative news service Meduza reports the doctor was told he must have been contaminated on a recent holiday to Thailand. There he must have eaten seafood tainted by Japan's Fukushima disaster in 2011, he was told.
"Caesium-137 … has the feature of accumulating in fish, mushrooms, lichens, algae," a medical office statement reads. "With a certain degree of probability, we can assume that this element got into the human body through the products of food."
Moscow continues to deny radioactive fallout from the blast is a problem.
"I'm not aware of it, I do not know what doctors you are talking about," President Vladimir Putin's spokesman Dmitry Peskov told reporters.
According to the Moscow Times, doctors at the Arkhangelsk Regional Clinical Hospital weren't told three bodies delivered to their morgue might have been radioactive.
Surgeon Igor Semin posted on Russian social media that officials "did not warn anybody — they threw them under a bus and let us sort it out".
But such expressions of outrage were quickly silenced.
Agents from Russia's FSB intelligence agency reportedly descended on the hospitals. Doctors and nurses were compelled to sign nondisclosure agreements and destroy hospital records.
Unconfirmed reports suggest up to 10 hospital employees have since been taken to a specialist radiation hospital in Moscow.
Russia's national weather and environment monitoring agency, Rosgidromet, released a report stating its sensor stations had indeed picked up radioactive fallout. This included Strontium-91, Barium-139, Barium-140 and Lanthanum-140 — isotopes have radioactive half-lives of between 1.5 hours and 13 days.
They are also products of nuclear fission: the process nuclear reactors use to convert uranium-235 into heat and energy.
Norway's nuclear treaty monitoring agency says it detected two explosions at the Nyonoksa naval weapons testing range on the day of the incident.
"We registered two explosions, of which the last one coincided in time with the reported increase in radiation," Norsar chief executive Anne Stroemmen Lycke told Reuters. "Both blasts were registered on our infrasound system. The first was also picked up by seismology".
This coincides with unconfirmed accounts that a Skyfall nuclear-powered cruise missile fell into the ocean upon launch, with the reactor detonating as a recovery team attempted to haul it out of the water.
Rosatom says five employees were killed in the accident. Two Russian military personnel were also reported to have died. Radiation levels in the nearby city of Severodvinsk then spiked some 16 times above average for 30 minutes.
Now, Moscow's contradictory statements are fuelling fears of a cover-up.
Speaking in Helsinki last week, Putin said Moscow could not reveal everything about the blast because of its military nature.
But that does not explain the potential breach of the nuclear test ban treaty. Several Comprehensive Test Ban Treaty Organisation (CTBTO) nuclear monitoring stations in the area of the test facility were shut down.
"This was a troubling development that suggests an attempt to conceal radionuclide data," writes Federation of American Scientists analyst Ankit Panda.
A CTBTO map of likely fallout patterns based on weather conditions at the time project the contamination would have spread southward, over Russia's densely populated eastern regions and into the Middle East. Most of the disabled sensor stations would have detected such a cloud had it been produced.
Peskov said suggestions the explosion had produced a radioactive cloud were "absurd".
Instead, he launched an attack on independent Russian media for attempting to "distort reality".
"Have you not tried to look at the situation from a different side?" he asked. "The way the situation unfolds makes it seem like somebody intentionally wants to escalate the media coverage around this, distort reality and present the situation as if there are reasons to be worried about the danger."
Jamie Seidel is a freelance writer. Continue the conversation @JamieSeidel