The following are jurisprudence on Warrantless Searches and Seizures

PEOPLE vs. SARAP  G.R. No. 132165

A search may be conducted by law enforcers only on the strength of a warrant validly issued by a judge as provided in Article III, Section 2 of the Constitution. Articles which are the product of unreasonable searches and seizures are inadmissible as evidence, pursuant to Article III, Section 3 (2) of the Constitution. Warrantless searches and seizures may be made without a warrant in the following instances: (1) search incident to a lawful arrest, (2) search of a moving motor vehicle, (3) search in violation of custom laws, (4) seizure of the evidence in plain view, (5) when the accused himself waives his right against unreasonable searches and seizures, (6) stop and frisk and (7) exigent and emergency circumstances. These instances, however do not dispense with the requisite of probable cause before a warrantless search and seizure can be lawfully conducted. In warrantless search cases, probable cause must only be based on reasonable ground of suspicion or belief that a crime has been committed or is about to be committed

People v. Ramos, G.R. Nos. 101804-07

The rule is that a search may be conducted by law enforcers only on the strength of a search warrant validly issued by a judge.

This is enshrined in the Bill of Rights. Such a rule, however, is not without exceptions. For instance, a warrantless search made be validly made as an incident to a lawful arrest or in stop and search situations. Another recognized exception is when the accused himself waives his right against unreasonable search and seizure

PEOPLE vs. DORIA G.R. No. 125299

Our Constitution proscribes search and seizure without a judicial warrant and any evidence obtained without such warrant is inadmissible for any purpose in any proceeding. The rule is, however, not absolute. Search and seizure may be made without a warrant and the evidence obtained therefrom may be admissible in the following instances:(1) search incident to a lawful arrest; (2) search of a moving motor vehicle; (3) search in violation of customs laws; (4) seizure of evidence in plain view; (5) when the accused himself waives his right against unreasonable searches and seizures.