Biology implements its own blockchain, kind of, so it's pretty easy to track down a common ancestor with enough samples. The oldest one gives you the release lo

Biology implements its own blockchain, kind of, so it's pretty easy to track down a common ancestor with enough samples. The oldest one gives you the release location and potentially some information about where it was sourced/created if you have enough information from before the event-- For example, tracking anthrax down to a sample collected from a specific farm during a cattle outbreak and then looking at people who were in the area. In contrast, software viruses don't accumulate changes unless they're under active development. Chemical and nuclear stuff can possibly be attributed by looking at isotopic composition or impurities, to determine manufacturing process. But doesn't really tell you anything unique. Exceptions are e.g. polonium which where only a few state agencies are known to be able to make it. The classic, scary chemical weapons (e.g. cholinesterase inhibitors, Sarin) themselves are kitchen chemistry. Ricin, even nastier to die from, is barn chemistry in that it's essentially castor bean tea. However, I suspect that people who manufacture on the cheap usually kill themselves and anyone with enough knowledge and resources to not kill themselves often don't want to make chemical weapons.