When you’re arrested for a crime, you’re presumed innocent until proven guilty. But sometimes, the justice system doesn’t work properly. Innocent people can be convicted, and it happens more often than you might think. There are a number of reasons why wrongful convictions occur.

Eyewitness mistakes

Usually, when someone is convicted of a crime, it’s because there’s eyewitness testimony against them. But eyewitnesses can be wrong. Unfortunately, human memory is often fallible, and people can misidentify a suspect, especially if they’re under stress or if the perpetrator is of a different race than they are.

In addition, police officers can sometimes inadvertently bias a witness. For instance, if an officer suggests to a witness that they saw the defendant commit the crime, the witness is more likely to say that they did, even if they didn’t actually see it.

Faulty forensics

Forensic evidence, such as DNA and fingerprints, is often key in convicting someone of a crime. But sometimes, this evidence can get misinterpreted or mishandled. For example, DNA evidence can be contaminated if it’s not properly collected or stored. In addition, forensic experts may have personal biases that influence their interpretation of the evidence.

Fingerprints can also get misinterpreted. For instance, two people may have similar-looking fingerprints, or a print may be partial and therefore not a good match for anyone.

False confessions

Sadly, sometimes people confess to crimes they didn’t commit. This can happen for a number of reasons. For instance, people may get coerced or threatened by the police into confessing. Or, they may have a mental illness that causes them to believe they did something when they didn’t.

People with intellectual disabilities are especially vulnerable to false confessions. They may not understand their Miranda rights, or they may be more likely to cave under interrogation.

Inadequate legal representation

Everyone is entitled to a lawyer, but not everyone can afford one. And even if you can afford a lawyer, that doesn’t mean you’ll get a good one. In some cases, public defenders tend to get overworked and don’t have enough time to properly investigate their clients’ cases. This can lead to wrongful convictions among innocent people just because their lawyers didn’t have the time or resources to build a strong defense.

Wrongful convictions are a travesty of justice. But by understanding why they occur, we can work to prevent them in the future.