The biggest mistake I see is using the wrong terms. We get tripped up by the things we don’t check because we think we already know them. Many people learned what they know about criminal law from TV – and on TV, every prosecutor is a DA, or district attorney. In reality, terms vary widely. In federal court, the prosecutor is the U.S. Attorney, or an Assistant USA. In state court, terms depend on how the system is organized geographically. In states like mine – Montana – where each county has its own elected county attorney with a hired staff, the county attorney handles all criminal cases and any civil cases involving the county. That person may also be called “the county prosecutor,” “state’s attorney,” or “commonwealth’s attorney.” Some states, like Connecticut and New Mexico, divide the responsibility by district. Others confuse the issue by using both terms – in New York, for example, the prosecutor is actually called the “county district attorney.” If you’re not sure what terms are used in your story state, check this list of prosecutors’ websites, http://207.74.121.45/Prosecutor/PA-West.htm#MT.

Similarly, state court names and structures vary. Before you call the general trial court in your story the Superior Court, District Court, or even the Supreme Court (used only in New York), check the National Center for State Courts’ list of websites, http://www.ncsconline.org/D_KIS/info_court_web_sites.html#nebraska

You don’t need a warrant to make an arrest. How often does a fictional law enforcement officer let a suspect go because he doesn’t have an arrest warrant? An arrest warrant is a determination by a judge that sufficient probable cause exists to detain a specific person on suspicion of a specific crime. But in most cases, the officer can make an arrest on the spot if he’s got probable cause. How does he get it? Through investigation – or sometimes, by actually witnessing the crime.

Confusing “evidence” with “proof.” Direct evidence is testimony or physical evidence of a fact. Circumstantial evidence is evidence of one fact that leads to an inference or presumption of another fact. Circumstantial evidence is enough to prove a defendant’s guilt. It’s also critical during an investigation, leading officers from one clue to another – and maybe, finally, to direct evidence or to enough circumstantial evidence to get a conviction.

Consider fingerprints found on the front door knob at the scene of a crime. They establish that a particular person touched the door knob, but they don’t prove that he went in or that he committed the crime inside. Using that direct evidence of his presence, officers can investigate further – and may uncover direct evidence of his guilt, such as eyewitness testimony that he shot the victim, or more circumstantial evidence, such as a cartridge shot by a gun he owns. The fingerprints don’t prove the suspect’s ultimate guilt – but they make his presence inside more probable, and help investigators build a case, piece by piece, against him.

Mistakes in Miranda warnings. Miranda is the U.S. Supreme Court case holding that a suspect who is in police custody can’t be questioned until he’s been warned of the potential consequences of answering. Miranda warnings are only required if the person is in custody and is being questioned. If he would reasonably believe he’s free to leave, he’s not in custody – and your fictional detectives and prosecutors can ask anything they want. If your detectives are discussing between themselves about how brutal the assault was, and who could do such a thing to a nun, and the suspect volunteers that she had it coming, that he’d wanted to kill her since the fourth grade, and he wished he’d done it sooner – well, that confession is admissible even if he hadn’t been warned, because it was made voluntarily and not in response to questioning. Smart officers know that not warning a suspect can be an important tool – once he’s warned, he may clam up.

As always, be aware that there are some state-by-state variations in what warnings are required and when.

Cops rushing in. For the sake of drama and brevity, TV cops often rush into the suspect’s home with stopping to pass go. In real-life, they need a search warrant, consent, or exigent circumstances. The warrant requires going to a judge with a written application and affidavit setting out specific reasons for believing evidence of a particular crime will be found in the location to be searched – that is, proving probable cause.

Consent to enter must come from a person who reasonably appears to have the right to consent. The person giving consent does not have to be a resident. Nor does it have to come from an adult. Can a kid give valid consent? Depends on age and circumstances. A sixteen-year-old, probably. A six-year-old, no.

"Exigent circumstances" are simply emergency conditions that justify an officer going into a resident without a warrant or consent, typically to prevent the commission of a crime or the destruction of evidence. Other examples: an apartment door opens and the officer sees a person inside who notices the officer, grab something off a table, and dashes to the bathroom. The officer reasonably concludes that the person intends to dispose of drugs, so he dashes in. Or he sees someone head out the back door, a window, or to a fire escape; he runs in to prevent the person from fleeing. A more extreme case: the officer sees or hears a person inside beating someone, and goes in to stop the assault and help the victim.

Assuming a felon can’t vote or own a gun. Recent election challenges have made us more aware of restrictions on voting by persons convicted of felonies. A handful of states bar them from voting for life. Others see voting as an important part of reintegration into the community. The trend is toward allowing persons who have completed their sentences to vote.

Other rights limited in some states include gun ownership, jury service, and holding public office. Federal convicts are barred from gun ownership for life. State laws vary widely, and may depend on the type of crime committed – obviously, violent crimes or those involving guns are more likely to trigger a ban. Some states permit a felony conviction to be considered in employment or in licensing.

Referring to guilt in a civil suit. My personal pet peeve. In criminal cases, defendants may be found guilty or not guilty (also called acquitted). But in civil cases – examples are suits for money damages for medical malpractice, for injuries from a car accident or contaminated peanut butter, or for wrongful discharge – there is no guilt or innocence. A defendant is liable or not liable.

The law can be confusing. State and federal laws vary tremendously. The range of possibilities may be overwhelming. But if you take time for a little research – to check the things you think you know and those you don’t – you’ll discover terrific opportunities to twist, deepen, complicate – or simplify – your story. Get the details right, and you can’t go wrong.

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