William J. Brennan, Jr., Ker v. California — Concurrence-dissent
“ The first is that any exception not requiring a showing of such awareness necessarily implies a rejection of the inviolable presumption of innocence. The excuse for failing to knock or announce the officer's mission where the occupants are oblivious to his presence can only be an almost automatic assumption that the suspect within will resist the officer's attempt to enter peacefully, or will frustrate the arrest by an attempt to escape, or will attempt to destroy whatever possibly incriminating evidence he may have. Such assumptions do obvious violence to the presumption of innocence. ”
