I believe the answer is: <span>reasonable suspicion
</span><span>Investigation under reasonable suspicion would give negative backlash if proven to be abused by the officers, but it still give them legal stand point to conduct a search on private properties.
Officers need to find things such as blood evidence, screams, or gun shots to conduct searches under reasonable suspicion.</span>
This is called monogamy as opposite to polygamy (multiple spouses at the same time).
