What can invalidate arrests and evidence seized during a search?

An arrest or evidence obtained during a search can be invalidated when there is illegal entry into a building. The Fourth Amendment of the U.S. Constitution protects against unreasonable searches and seizures, and any evidence gathered from a search that violates this protection can be deemed inadmissible in court. If law enforcement officers enter a property without a valid warrant, probable cause, or the homeowner's consent, the entry is considered illegal. This violation undermines the legitimacy of any subsequent arrests made or evidence discovered during that unlawful entry.

In contrast, the other options involve scenarios where the legality of the actions taken by law enforcement is upheld. For instance, legally obtained warrants provide officers with the authority to enter a property, while consent from the homeowner grants permission for entry. Additionally, while using forceful entry may raise questions about excessive force or procedural appropriateness, it does not automatically invalidate the arrest or evidence unless accompanied by other illegal actions. Hence, the core concept is that illegal entry directly contravenes constitutional protections, leading to the invalidation of both arrests and any evidence procured as a result.