One evening in February, as Ivan Gorlovko was burying his dog in the frozen yard behind his house in Chuhuiv, 25 miles south-east of Kharkiv, he heard a screech of tyres and looked up to see a convoy of Ukrainian army trucks on the bridge over the Siverskyi Donets. The link between Laika’s death and the military vehicles on the bridge was not accidental as far as Gorlovko was concerned. He was sure the trucks belonged to the Security Service of Ukraine and were transporting dangerous pathogens from the Chuhuiv Bacteriological Institute to a place of safety in the west of Ukraine in case of a Russian invasion. The CBI is part of Kharkiv’s Centre for Disease Control and Prevention, which along with a similarly named outfit in Poltava, eighty miles west, is funded by the US government. ‘Joe Biden killed my dog!’ Gorlovko claimed. ‘But what can a poor Ukrainian dog-owner do if our American masters are developing dangerous bioweapons in those labs.’

Andrew Weber, a former US assistant secretary for nuclear, chemical and biological defence programmes and now a director of the Arms Control Association, told Agence France Presse that the US Defence Department ‘has never had a biological laboratory in Ukraine’. The department’s funding of the Kharkiv and Poltava Centres for Disease Control and Prevention through its Biological Threat Reduction Programme is a matter of public record, however, and openly acknowledged by Washington as part of a joint effort to deactivate biological agents and prevent the outbreak of disease.

An American diplomat in Kyiv told me that Ivan’s ‘dead dog’ story was just ‘Russian disinformation’, adding: ‘I don’t wish to intrude on a dog-owner’s grief but it’s just a misperception that America creates bioweapons. We’re working with Ukraine to neutralise bioweapons because, don’t forget, the Soviet Union had the largest biological weapons programme ever created, which explains our presence in such facilities helping respond to any bioweapons outbreak. Our researchers and officials work with their Ukrainian counterparts to isolate toxins of security concern while also undertaking peaceful research and vaccine development that has recently played an important role in stopping the spread of Covid-19, by the way.’

Unsurprisingly that isn’t quite how the Russian Ministry of Defence sees it. A couple of days before the outbreak of war, Moscow’s charge d’affaires in Kyiv – there hasn’t been an ambassador in place since the invasion of Crimea in 2014 – picked up a message about the dead dog that Gorlovko had posted on a Telegram channel, and passed it upwards to the Kremlin. The story piqued the interest of Igor Kirillov, the head of the Russian military’s Radiation, Chemical and Biological Defence Forces, who delights in circulating fake information about the development of nuclear weapons and Western-run biological weapons laboratories. On 23 February, in a transparent attempt to justify the imminent invasion of Ukraine, Kirillov declared on Russian state television that ‘the latest analysis by our experts confirms the work of US scientists on pathogens of diphtheria, dysentery, dengue and African swine fever laboratories in Kharkiv and Poltava.’

He went on to imply that the Kharkiv and Poltava labs were developing pathogens specifically directed at the ‘Slavic ethnic group’ as part of a genocidal attack on the Russian-speaking inhabitants of the Donbas. ‘Since 2014, during which time more than 14,000 have died in Luhansk and Donetsk, there has been a ten-fold rise in cases of tularaemia and other infectious diseases among servicemen and residents of the people’s republics.’ Unfounded allegations of genocide in the Donbas have been repeatedly cited by Putin as a pretext for ‘liberating’ the east of the country.

Gorlovko, unlike Kirillov, doesn’t really fit the profile of a conspiracist. He doesn’t use the internet or watch TV and he doesn’t like politics. His parents were Russian, born in Belgorod, just over the border from Chuhuiv, and although he regards himself as a proud Ukrainian, he told me he was unwilling to take sides. He was angry about Laika’s mysterious death and had posted his allegations on Telegram as a way of coping with his bereavement, but he was also confused, which made him more susceptible to conspiracy theories. The inhabitants of Chuhuiv have been shelled from both sides and engulfed by propaganda, rumour and fear.

Chuhuiv was bombed on the first day of the invasion, 24 February, along with Chernobyl in the north-west and Zaporizhzhia – the largest nuclear power plant in Europe – in the south-east. The last eight months have brought back fears of weapons of mass destruction, thanks in part to Putin’s nuclear threats and his reckless disregard for human safety in shelling the Zaporizhzhia atomic facility (which Kirillov tried to blame on the Ukrainians). After the seizure of Chernobyl in February, unprotected Russian soldiers camped on contaminated soil and inhaled contaminated dust. There were reports of at least one death from radiation poisoning. Meanwhile cruise missiles were flying over the Chuhuiv Bacteriological Institute and slamming into nearby trees.

The long rows of silver birches add a bleak splendour to Chuhuiv’s industrial post-Soviet landscape, which in spite of the smoke, dirt and neglect is still reminiscent of the 19th-century paintings of Ilya Repin, one of the aesthetic cornerstones of Russian nationalism, even though Repin himself was Ukrainian, born in Chuhuiv in fact. Another Chuhuiv-born artist, Olexey Viznavsky, took me on a fifty-mile drive south along the banks of the Seversky Donets to Izium, recaptured from the Russians a week before. He had volunteered to deliver humanitarian aid. The bridge in Chuhuiv was destroyed in March and we got lost several times on back roads through farmland dotted with the wrecks of tanks and ruined barns gouged with mortar holes.

Viznavsky was impatient with Gorlovko’s bioweapons claims. ‘It’s a kind of madness to see conspiracy everywhere,’ he said. ‘Is it madness to be preoccupied by the danger of weapons of mass destruction?’ I asked. Eight months after Russia launched its invasion, Putin’s army has been driven back in the Kharkiv region, while Ukrainian forces are advancing in the Donbas and squeezing enemy troops and supply lines in Kherson, the gateway to Crimea. On 21 September, facing humiliation, Putin issued a new threat: holding ‘referendums’ in the occupied regions of Donetsk, Luhansk, Zaporizhzhia and Kherson, which could lead to them being annexed by Russia any day now.

The city of Zaporizhzhia and other parts of the region are not occupied by Russian troops and won’t be participating in the bogus voting exercise. Two days before Putin’s announcement I was in Orikhiv on the frontline. Ruslan Mikhalenko, a 24-year-old accountant, had joined the army three months earlier and was now stopping cars at a checkpoint on the edge of town. There was no electricity or gas or running water in Orikhiv, he said, as a shell whistled over our heads.

Later, after the referendum announcement, Mikhalenko texted me to say that Putin was hoping to make the ‘special military operation’ more legitimate in the eyes of ordinary Russians by turning the invasion of a neighbouring country into a defensive war. But other Ukrainians worry that Putin may exploit the annexations to launch a nuclear attack if the war swings decisively against him. ‘I’m not bluffing,’ he warned on television, but isn’t that what buffers always say? Viznavsky asked me if I was wary (ostorozhniy) of being caught up in a nuclear incident. ‘That’s one word for it,’ I said.

We were standing in a silver birch forest just outside Izium where investigators had uncovered a mass grave of local people killed by the Russian occupiers. On the way back to the car, Viznavsky and I walked up Izium’s newly renamed John Lennon Street, past a mural of the former Beatle emblazoned with the words, in Russian, Daite miru shans (‘Give Peace a Chance’), but I’m not sure that’s really in Putin’s playbook.