To summarize, scientists have figured out that the HIV virus first entered the human population around 100 years ago. They figured this out by estimating the rate of mutation in two separate strains of the virus, then tracking the two strains back to a common ancestor. The probable event was the butchering of a hunted chimpanzee for dinner. If the hunter got a cut in the process of butchering, and some of the Chimp blood goes in, there is where it would all start. Nobody was there to photograph this suspected event, but you have to realize that not every event in human history in the past century was photographed.
Let's have an end to the conspiracy theories about HIV coming from biological warfare labs, please. They did not have biological warfare labs in 1908.