The man attacked people in the streets of Irkutsk, stabbing one passerby to death and injuring two others, both pensioners.
None of the numerous witnesses moved to intervene or even alert police, who were only informed about the incident by one of the surviving victims, said cops.
A citywide search resulted in the man being tracked and detained. He fled his home in an unsuccessful attempt to evade arrest, abandoning his dinner that consisted of dog meat.
The suspect, whose name was withheld, pleaded guilty, but failed to explain why he stabbed people or ate his dog.
A case was opened on charges of intentionally inflicting grave bodily harm, punishable with up to 15 years in prison.