Question

A key element of the Fourth Amendment is that searches and seizures must be conducted

only if a serious crime has been committed.
with compassion and support.
using a practical and organized method.
based on reasonable belief that a crime has been committed.

Answer 1

based on reasonable belief that a crime has been committed.

The Fourth Amendment requires searches and seizures be reasonable—generally meaning supported by probable cause (a reasonable belief that evidence of a crime or a crime has been committed) and, absent exceptions, a warrant describing the place and items/persons to be searched.