Crime scene evidence is of vital importance in making a viable case against a criminal suspect. However, police officers must be careful that their crime scene investigations are lawful, according to the U.S. Supreme Court and their local jurisdictions. Crucial evidence may be thrown out of court and murder convictions overturned if police officers unlawfully enter and search a premise. Several U.S. Supreme Court decisions are discussed as examples of the fourth amendment rights of criminal suspects, including Mincey v. Arizona (1978), Thompson v. Louisiana (1984), and Flippo v. West Virginia (1999). The main lesson of these court cases is that there is no homicide exemption to the privacy expectations provided by the fourth amendment. Search warrants are necessary where the victim and the suspect share a proprietary right to the premise in question. Case studies are offered throughout the article to illustrate key points and legal rulings. Underscored throughout the article is the importance of properly securing crime scenes, obtaining search warrants where necessary, and carefully collecting and preserving all pieces of possible criminal evidence.