Police officers will sometimes ask a magistrate for permission to serve a warrant unannounced, which often involves the forcible entry into a home during a criminal investigation. The judge has to allow a special exception to normal procedures for this sort of request, and it’s based on a risk assessment of the suspect(s), the location, and the potential for the destruction of crucial evidence. 

In a perfect world, investigators collect enough evidence during their investigation that we can make an arrest away from the home and serve a search warrant on an unoccupied residence to avoid the risk. In many cases, that is unfortunately difficult or impossible to accomplish. The evidence that leads to a search warrant or even an arrest is often only enough to get our foot in the door. Warrants and arrests are based on a legal standard called probable cause, but the evidence needed to turn those into a conviction at trial, “beyond a reasonable doubt,” is a heavier burden. Investigators try to fill this gap in the system with enough evidence and details to convince a jury for a guilty verdict. Additional details, like the possession of proceeds from a criminal enterprise (money or other assets, such as keys to that fancy car parked out front), and the placement of items in proximity and relationship to other people, often make a difference. Consider how quickly you can round up your dirty clothes when a friend unexpectedly knocks on your door. 

Some people are convinced that few circumstances sufficiently outweigh the risks of an unannounced warrant. Odds of misidentification of the police are high, and the reaction of a person under duress or woken from sleep is difficult to predict. But like any alternative to a problem—there are trade-offs. Done correctly, officers can access a home before a suspect has a chance to react at all, and before they come to terms with the consequences of their crimes. Critical details may guarantee a conviction, which might help keep violent offenders locked up.

The key is flexibility. No-knock warrants give us the ability to gain initiative—to be proactive, rather than reactive. It’s not always the best alternative, but it is an important option to have available. These situations require exceptional training and meticulous risk-management—Consider what the headlines will say if we make a mistake. We are only as good as our last undertaking. There is a reason that we have to get special permission for this sort of thing—With the ability and authority to keep this option on the table, comes the burden to get it right. It’s on us to perform accordingly.