MH17 was shot out of the air on July 17, 2014, killing all 298 passengers on board. Most experts say the plane was most likely struck by a Buk anti-aircraft missile, a type commonly used by Ukrainian and Russian forces.
Shortly after the crash, Russia's defense ministry presented satellite images it said showed Buk missile launchers belonging to Ukraine's army near the eastern city of Donetsk in the days around the shooting-down, meant to imply that the Ukrainian army had hit the plane.
After 30 pages of analysis, Bellingcat says "unequivocally" that these images have been digitally altered so as to falsely appear that they were taken in the days around the crash. The photos were actually taken in the first half of June, the report says.
Besides the altered dates, Bellingcat says the photos exhibit many signs of being Photoshopped, apparently to conceal objects that would betray they were taken a month before -- adding cloud cover for example.
The group says it is clear proof that Russia's government has lied in connection with the crash.
"These claims, representing the majority of information publicly presented by the Russian government since the downing of Flight MH17, are a clear attempt by the Russian government to deceive the public, global community, and the families of the Flight MH17 victims," Bellingcat said in a statement released with the report.
The downing of MH17 caused outrage around the world and prompted western countries to impose harsher sanctions on Russia for its role in arming pro-Russian separatists.
Since then Russian authorities have churned out different theories laying blame on Ukraine's military, falsely claiming a Ukrainian fighter-jet had been nearby and giving a false flight-plan for MH17; the separatists have even suggested the plane was full of corpses before it took off.
Bellingcat says it has now proved four major statements by the Russian defense ministry on MH17 as deliberately false. It adds to a growing pile of evidence that Russia's government is trying to conceal its military's activity in eastern Ukraine; modern tanks, only in use by Russia, have been repeatedly spotted and serving soldiers have posted on social media showing themselves fighting.