I believe I read that Indians were given smallpox infected blankets during colonial times.
There was a proposal to do that by a British officer but nothing came of it.
There was, however, an epidemic of smallpox among Indians following a period of raids and looting of white settlements already afflicted by smallpox, including a situation where the French-Indian side captured a British fort where smallpox had broken out, and the natives stole everything that wasn’t nailed down from the room where smallpox patients had been quarantined. Of course in this case the infection was not intentional it was pure ignorance.
There was another case some time after the Louisiana purchase where an outbreak occurred among the friendly Mandan Indians that was alleged by a wannabe Indian nutty professor named Ward Churchill to be deliberate- from trading infected blankets from a steamboat, but the allegations did not hold up to scrutiny; the outbreak was not intentional.
You did read that. Liberals have been spreading that propaganda for the last 50 years. Some years ago I read a great article that explained that this was a false claim. It not only took issue with the claimed source material for this accusation, it pointed out that the germ theory of disease did not come about until the latter 1880s. In the 1760s, nobody knew anything about viruses or bacteria. They thought disease were caused by "Influenza ad Astra" (influence of the stars) or "Malaria". (Mal-Aria meaning "bad air")
They literally had no knowledge of germs or disinfectant or sanitation.