An officer knocks on the door, and when the door is opened he sees prohibited matter. He would be allowed to enter and secure the evidence under the plain view doctrine. If in the course of securing the visible evidence he sees other evidence, that would also be allowed.
An officer asks for and is granted permission to search by a person apparently in control of the premise.
warrant and warrantless searches
It prohibits warrantless searches and seizures.
(Answer is applicable to the USA only): A warrantless arrest is never served. A warrantless arrest is performed. Following the warrantless arrest, the arresting individual (typically) or authority is required (usually) to provide the courts with a warrantless arrest affidavit wherein the person making the arrest articulates the probable cause for the arrest, which then is submitted to a judge for review. The arrested person will already be in jail or otherwise in custody (and possibly even bonded out), before the signed warrantless arrest affidavit becomes available to the arrested person.
Yes.
Conduct warrantless searches in the interest of national security
(in the US) As much as some activist parties would like you to believe they are - they are NOT. The chief reason being that anything discovered during a warrantless search is not admissible in court and is therefore worthless as evidence.
Warrantless searches can be performed when consent is given or there are exigent circumstances. An exigent circumstance is if the police feel that someone's safety is at risk or criminal activity is ongoing. Two other conditions are the plain view doctrine and incidental searches.
The scope of a valid warrantless vehicle search is not limitless. It is generally limited to areas within the immediate control or reach of the driver, where there is a reasonable belief that evidence of a crime may be found. Searches that go beyond these limitations may be considered unreasonable and violate the Fourth Amendment protection against unreasonable searches and seizures.
To protect its citizens from terrorist attacks
To protect its citizens from terrorist attacks
United States, 267 U.S. 132 (1925), was a decision by the United States Supreme Court that upheld the warrantless searches of an automobile, which is known as the automobile exception. The case has also been cited as widening the scope of warrantless search.
To protect its citizens from terrorist attacks