A more thorough explanation:

Probable cause is a legal requirement that police officers must meet before making an arrest, conducting a search, or receiving a warrant. It is based on the Fourth Amendment of the United States Constitution, which states that "no warrants shall issue, but upon probable cause."

Probable cause is usually established when there is a reasonable basis for believing that a crime may have been committed or when evidence of the crime is present in the place to be searched. Under certain circumstances, probable cause can also justify a warrantless search or seizure.

• If a police officer sees someone breaking into a car, they have probable cause to arrest that person for theft.
• If a police officer smells marijuana coming from a house, they have probable cause to obtain a search warrant for that house.
• If a police officer is in hot pursuit of a suspect who has just committed a crime, they have probable cause to enter a private property without a warrant.

These examples illustrate how probable cause is based on the specific circumstances of each case. It is not a fixed standard, but rather a flexible concept that depends on the facts and context of each situation.