It is important to separate the known facts from the allegations being made and suspicions voiced by Western officials.
What is beyond doubt is that this year has seen a succession of suspicious fires at cargo depots in the UK, Germany and Poland - suspicious enough to trigger investigations by counter terrorism police.
There have been other incidents across Europe and last month a man was convicted at the Old Bailey under the new National Security Act for an arson attack on a Ukrainian-owned business in Leyton, east London in March.
In Germany, the head of the domestic intelligence agency (BfV) has said it was only by a stroke of fortune that the Leipzig device had not ignited in mid-air.
BfV head Thomas Haldenwang has described the device that caught fire at DHL's logistics hub at Leipzig-Halle airport as suspected Russian sabotage.
Taken together, these events are leading Western governments to conclude there is a strong possibility that Russia’s GRU military intelligence agency has embarked on a systematic campaign of anonymous, covert attacks on those countries helping Ukraine.
The package that burst into flames in Leipzig is thought to have arrived from Lithuania and its onward flight was delayed.
The device that caught fire in Minworth is also understood to have come from Lithuania, where the head of the parliament's national security and defence committee, Arvydas Pocius, said it was part of an ongoing campaign of hybrid attacks aimed at "causing chaos, panic and mistrust".
DHL has increased security since the recent freight fires. "DHL Express has taken measures in all European countries to protect its network, its employees and facilities, as well as its customers' shipments," a spokeswoman said a few weeks ago.
Poland's government has already responded to alleged Russian sabotage, with Foreign Minister Radoslaw Sikorski announcing the closure of a Russian consulate in Poznan and threatening to expel the Russian ambassador if it fails to bring an end to its attacks.
Russia's foreign ministry condemned the move as "a hostile step that will be met with a painful response".