Garbed in camouflage military fatigues, helmets, heavy black boots, and gripping what appear to be automatic weapons, the group poses for a picture with an unfurled Bulgarian flag in a field backdropped by a row of trees.
The picture was uploaded on March 24 on the Facebook page of the so-called Macedonian-Bulgarian Foreign Battalion "Todor Alexandrov," a reference to a leader of the Internal Macedonian Revolutionary Organization (VMRO) who was active during and after the period of Ottoman rule in the Balkans. According to that social-media account, the group are deployed in Ukraine to fight against invading Russian forces.
Soon after the Facebook page emerged, articles about the group appeared in Bulgarian media, including interviews with members of the alleged fighting force, talking about their mission and appealing for donations.
Shortly after Russia invaded Ukraine on February 24, Ukrainian President Volodymyr Zelenskiy appealed to foreigners willing to help defend Ukraine and join the fight. The government even set up a website for them to join the international brigade, which is now thought to number in its thousands.
The Macedonian-Bulgarian Foreign Battalion, however, doesn't appear to be among them.
Grilled in parliament in April about the alleged fighting force, Bulgarian Defense Minister Dragomir Zakov said the Facebook photos were fake.
Some analysts and commentators parsed Zakov's words, noting that he said the photos were fake but did not explicitly state that the battalion was fictitious as well.
Most if not all the clues to the group's existence come from social-media posts.
The adage that truth is the first casualty of war seems even truer in the age of social media. During the Russian invasion of Ukraine, fake news has metastasized across social media, much of it doctored video of battles that never occurred or in the past somewhere else.
RFE/RL's Bulgarian Service examined images uploaded on the group's Facebook page and found all were either from years ago or appeared to have been purloined from other sites.
One image, for example, purporting to show Bulgarian or Macedonian fighters, appeared to actually be Belarusians. "Good evening, we are in Ukraine! Greetings from us and our Georgian and Ukrainian brothers!" reads the text accompanying the photo uploaded on the group's Facebook page on March 24.
However, RFE/RL found the photo bears a striking resemblance to another of what appears to be the same group. Instead of a Bulgarian flag, a red-striped, white banner of the Belarusian opposition is unfurled, along with an black anarchist banner.
The image first appeared to have been published in a Telegram channel of a group of Belarusian fighters inside Ukraine on March 23, a day before it appeared on the Bulgarian battalion Facebook page.
Another photo, published on May 16, shows fighters from the Ukrainian Volunteer Corps of the nationalist Right Sector swearing allegiance to the Ukrainian people.
The original image dates to at least two days before it was added to the post of the "Macedonian-Bulgarian Battalion."
Coincidence or not, the colors of the Right Sector banner -- red and black -- are the same as those of the VMRO, an early 20th century group which was founded by anti-Ottoman Macedonian -Bulgarian revolutionaries.
The Facebook page of the Macedonian-Bulgarian Foreign Battalion also uses images that have nothing to do with the war in Ukraine.
Photos of drones, for example, which a March 19 posting claims were sent by a donor, can be found on various sites selling equipment, such as this one.
Krasi Panchev, who has been working as a contractor for a private military company for 14 years, appeared in a photo uploaded to the battalion's Facebook page. Panchev told RFE/RL that the photo had been taken in Bulgaria, in Plovdiv, not Ukraine, as purported on the Facebook page. Moreover, it was not a group of volunteers but Bulgarian military personnel, Panchev said.
Curious as to who may have been responsible, Panchev and others looked deeper, a probe that led to Ivan Belishki, a 22-year-old enthusiast for airsoft, a team game fought with air weapons. Ultimately, they contacted him and requested he remove the photo. Although Belishki denied any role in the Facebook page, the photo did eventually vanish from the social-media site.
"This is some kind of concoction of his," Panchev said of the Facebook site, pointing the finger at Belishki. "There is absolutely nothing like that, it doesn't exist," Panchev added.
Contacted by RFE/RL, Belishki, who set alight a Russian flag during a demonstration in Sofia in support of Ukraine in the early days of the Russian invasion, denied any role in the Facebook project.
"I have absolutely nothing to do with it," Belishki said. "Such allegations are not serious, and if anyone does make such claims, I'd like to know so that I can take legal action," he added.
RFE/RL contacted the Bulgarian Defense Ministry for comment on whether they were investigating the misinformation spread on the Facebook page. The ministry said it could not share more than what had been disclosed by Defense Minister Zakov in parliament.
RFE/RL also turned to the Bulgarian Interior Ministry, which declined to comment on whether a probe into the case had been launched. "Certainly, given that such information has been officially released, some action has been taken," the ministry said.
While the battalion may be nothing more than a social-media creation, sources tell RFE/RL that individual Bulgarians -- anywhere from 10 to 100 -- may be in Ukraine fighting.