The radio communications suggest that these weren't random, isolated events, but that it was systemic behavior designed to terrorize. And these atrocities weren't just done by mercenaries, or Chechens, or other groups well-versed in terrorism, but also young Russian conscripts as well as veteran forces. It was "normal."
Source: Der Spiegel
The Bundesnachrichtendienst (BND), Germany’s foreign intelligence service, has acquired gruesome new insights into the atrocities committed by Russian military forces in the town of Bucha near the Ukrainian capital of Kyiv. DER SPIEGEL has learned that the BND intercepted Russian military radio traffic in which the murder of civilians in Bucha was discussed. Some of the intercepted radio traffic can apparently be directly linked to dead bodies that have been photographed in Bucha.
...
The intercepted comments now appear to completely refute Russia’s denials. DER SPIEGEL has learned that the BND briefed parliamentarians on Wednesday about its findings. Some of the intercepted traffic apparently matches the locations of bodies found along the main road through town. In one of them, a soldier apparently told another that they had just shot a person on a bicycle. That corresponds to the photo of the dead body lying next to a bicycle that has been shared around the world. In another intercepted conversation, a man apparently said: First you interrogate soldiers, then you shoot them.
And perhaps most chilling of all,
The radio traffic intercepted by the BND makes it seem as though the atrocities perpetrated on civilians in Bucha were neither random acts nor the product of individual soldiers who got out of hand. Rather, say sources familiar with the audio, the material suggests that the troops spoke of the atrocities as though they were simply discussing their everyday lives.
Just routine.
The Russians have killed so many in Bucha that it's difficult to decide what picture of a man with a bicycle they're talking about.