Igor Girkin, the former Russian intelligence officer who once shot his own troops for insubordination, may have shot down the Malaysia Airlines flight MH17.
“We did warn you - do not fly in our sky," he reportedly posted to a social media page just hours ago.
The terrorising message, most probably aimed at the Ukraine government, was hastily deleted after it became clear that the jet was not a military aircraft, but a passenger jet carrying 298 people on board.
Amateur video has also captured the moment the militia commander, who also goes by the name of Strelkov or 'Shooter', was caught laughing with rebels as the plane was reduced to a fireball upon impact with the ground.
"That was a blast - look at the smoke!" the rebels gleefully bragged.
In the video, believed to have been filmed by the rebels themselves, 'Igor the Terrible' laughs as he announces that the plane was struck.
"Look at those black spots, these are the parts, flying... it was a blast.. look, look, black smoke!"
Just moments later, he tweeted a number of boastful messages under the impression that he had shot down an Antonov-26 military plane from the Ukranian Air Force.
"In the area Torez we just hit down An-26, it’s lying somewhere in the mine “Progress”," he tweeted.
"We warned you – do not fly in “our sky”. And here is the video confirmation of the “bird dropping”.
"Bird fell near the mine, the residential sector was not disturbed. Civilians are not injured."
The Ukranian secret service believes Strelkov is a man of mystery with at least three names, although his real identity is Igor Girkin.
According to the secret service, he has an ex-wife and children still living in Moscow where he is known as 'Igor the Shooter'.
He was blamed for the abduction of a number of peacekeeping officials from the Organisation for Security and Co-operation in Europe, where he accused them of being professionally trained spies who were carrying 'special devices'.