One aspect of criminal justice that confuses many writers is the legal justification for searches. On TV, detectives pretty much search whatever they want whenever they want without respect to the legalities involved. The Supreme Court has ruled that a warrant is needed to conduct a search except in a limited number of circumstances. For example, a driver can give consent to search his car. An officer can search a person she has arrested. A SWAT team could go into a warehouse to rescue a hostage.
Most searches are conducted without a warrant because of these “exceptions.” But when an exception to the warrant requirement does not exist, the officer must obtain a warrant.
There’s only one hangup—to obtain a warrant, there must be “probable cause” to believe there is evidence at the place to the searched. Without good reason, a judge will not issue a warrant.
The search warrant consists of two parts—the affidavit prepared by an officer attesting to the facts that establish probable cause and the command or order issued by a judge to conduct the search.
While you may not wish to get bogged down in the technicalities of affidavit preparation, avoid the mistake of mischaracterizing the process. The biggest mistake is inferring a warrant can be obtained in a matter of minutes. Some agencies are using electronicsubmission of an affidavit to a judge (still rather rare). Despite the modern shortcuts available, delays are common. The judge isn't standing by waiting for affidavits to come in. After hours is worse. Even with the advent of “e-warrants,” there must be a paper copy of the warrant to present to the occupants of the premises.
A significant part of obtaining a search warrant is preparing the affidavit that lays out the probable cause justifying issuance of a warrant. Depending on the complexity of the warrant, this could take an officer anywhere from fifteen minutes to several hours. It's got to be good. I wrote many “routine” drug search affidavits that took 30 minutes to type and 15-30 minutes to drive to the judge's location. That's if everything goes smoothly and the judge is where he's supposed to be and available. On the other hand, I've seen the process run to 1/2 day when the judge was on the bench, out at his lake house, or otherwise out of reach. It took me three hours to compose the affidavit on one of my murder cases.
A search is valid for up to ten days in most states, but it usually executed within the first 48 hours of its issuance. A length of the search depends on the nature of the crime. The search must end when the object of the search has been found. Processing a murder scene in a house can take from 8 hours to over 24 hours, spread over multiple days. In most states, you can hold the scene until the work is completed. That usually means keeping someone at the scene 24/7 to show the search is still "in progress." In some cases, execution of the warrant has gone on for a significant time of period, such as the search of John Wayne Gacy's basement where 26 bodies were buried. On average, however, the "typical" residential murder scene, if there is such a thing, is not held over two days.