Whether or not the cops were aware of Garners health problems are irrelevant. The cop knew the choke hold he used was illegal. Its illegal for a reason... Its becuase it's inhuman, harmful and evedentually results in peoples deaths...
The choke hold he used isn't illegal. Its not permitted by the department but he didnt break any laws by using it. I dont think it even was a choke hold since the man was able to speak when the cop had him in the headlock.