Answer:
4th Amendment
Step-by-step explanation:
The 4th amendment of United States constitution banned the government from conduct "unreasonable search and seizure."
Prior to the creation of this amendment, the Government has the power to mobilize the the police to conduct search on any properties even without a proper reason. After this amendment, Police need to show the citizens with a warrant in case they wanted to conduct a search on their private property.
There is one exception to this rule. Police can conduct a search without a warrant if they perceive an "imminent danger" (such as Gun shots , or violent scream)