Rape accusations present special challenges for law enforcement: Witnesses are generally absent, alcohol or illegal substances can be a factor, and consent—or its absence—can be impossible to prove.

A case featured in Thursday’s New York Times includes all three factors, along with further complications: Three months passed before charges were filed, the accusation was made not by the victim but by her boyfriend, and—most seriously—the alleged attacker, Greg Kelly, is a TV news anchor and the son of New York City’s police commissioner, Raymond W. Kelly.

The combination of he-said-she-said accounts and a high-profile defendant made this an exceptionally difficult case for the New York Police Department. Is the accuser credible? Why did she wait so long? Why didn’t she press charges herself? Did alcohol affect her behavior and her ability to remember what happened? Will the defendant’s prominence give him an unfair advantage as the investigation unfolds?

The Department decided to take the unusual step of asking the Manhattan District Attorney, Cyrus R. Vance Jr., to conduct the investigation. It’s an extraordinary situation: Robert M. Morgenthau, who had previously run the office for 35 years, said he could not recall a case in which the entire Police Department was left out of a criminal inquiry because of a potential conflict of interest.

Police departments in smaller communities can be thankful that they don’t have to operate in the glare of publicity that officers in New York take for granted. Still, any officer—even in the tiniest hamlet—can expect to encounter similar challenges: Scrutiny from the media, evidence that raises more questions than it answers, a defendant from a prominent family.

What guidelines can help officers function effectively under these difficult circumstances? The answer is surprisingly simple: Act in accordance with agency policies.

An officer’s duties include maintaining order, protecting public safety, investigating and collecting evidence, recording relevant information, and making arrests when necessary.

Officers are not authorized to try cases or make judgments: “None of this would have happened if you hadn’t been drinking.” “That was a stupid way to handle the problem.” “Do you seriously think I’m going to believe what you just told me?”

In a perfect world, criminals would be easy to spot, truth would be glaringly obvious, and the police would always be right. But experienced officers know that appearances aren’t always what they seem. Government officials break the law on occasion, petite women have been known to victimize burly men, and ordained clergy sometimes take advantage of delinquent youths.

Sexual assault cases, as we noted earlier, require exceptional sensitivity and caution. The wisest course of action for an officer is simply to handle each situation as professionally as possible, remembering that the best way to deal with mistakes is not to make them in the first place.

Jean Reynolds, Ph.D., is the author of Police Talk and The Criminal Justice Report Writing Guide for Officers. Visit www.YourPoliceWrite for free resources for writing better reports.