The police come into your house and can conduct a search of your home without a warrant in some limited circumstances. These circumstances basically fall within four situations:
1. Consent - If someone freely and voluntarily agrees to a search of his or her property, the police can search this property without a warrant.
2. The Plain View Doctrine: Police officers can legally search an area and seize evidence if it is clearly visible. If the police see an illegal act occurring outside of your home, they may perform a search and seize evidence from your home without a search warrant.
3. If a lawful arrest is being made. Police officers do not need a warrant to perform a search in connection with an arrest. If you are arrested for a crime, the police have the legal right to protect themselves by searching for weapons, evidence that could be destroyed, or accomplices to the crime.
4. Exigent Circumstances. If the police feel that the time it would take to get a warrant would jeopardize public safety or lead to the loss of evidence, they can perform a search without a warrant. For example, the police can forcibly enter a home if it is probable that evidence is being destroyed, if a suspect is trying to escape, or if someone is being injured.
If one of these situations is not involved, any evidence that the police seized during the search would be illegally obtained and not be allowed as evidence of a crime. In addition, if any evidence was obtained during an illegal search, they would not be able to use this evidence to obtain a legal search warrant the next day
Sometimes it is difficult to determine exactly if one or more of the the situations above is present. It depends a lot on the individual facts and circumstances present. If you believe that there is any question whether the police search was legal, it is highly recommended that you contact a local criminal defense attorney to completely protect your rights.