The checks and balances in place in the criminal justice system are not enough to prevent the wrong person from being convicted of a crime they did not commit. Nor does this system treat everyone equally. Thousands of wrongful convictions have been overturned after people have already spent years in prison. Without technological advances like DNA testing, many of those innocent people might still be behind bars.
After a criminal conviction, defendants only have a limited amount of time to file an appeal, which takes time, money, and effort. On top of this, defendants may have even more limited resources after going to prison. It can be difficult to win an appeal in a criminal case, and for many convicted defendants, that is where their court battle ends.
There are limited legal grounds to overturn a wrongful conviction. Appeals courts may only consider a petition for exoneration if the wrongfully convicted person can show evidence of misconduct by the prosecutor or police, newly-discovered DNA evidence, or other evidence to support reopening the case.
There are several causes for wrongful convictions, including mishandling of important evidence or intentional deception by police and prosecutors. Some of the leading causes of wrongful convictions include:
- Mistaken identification or eyewitness testimony
- False confession
- Unreliable or biased informants
- Inadequate assistance of attorneys
- Misconduct by police
- Misconduct by prosecutors
Even if a convict knows why they were wrongly convicted, they will need evidence to support their claim. This will most likely require the work of an experienced criminal defense appellate lawyer.
The Sixth Amendment of the Constitution guarantees criminal defendants the right to an attorney. A defendant expects their lawyer — even if it's a court-appointed lawyer — to be professional, qualified, and competent. Unfortunately, that is not always the case.
The Supreme Court determined that a criminal defendant has the right to an effective lawyer, in the 1984 case of Strickland v. Washington. To prove that a court-appointed lawyer provided ineffective assistance of counsel, the defendant has to show that:
- Their lawyer's performance was objectively deficient under the circumstance—in other words, that it fell below a certain standard; and
- It is reasonably likely that if the lawyer had performed up to the standard, the result would have been different for the defendant.
People like to think they are reliable with what they can see with their own two eyes. However, there are several problems with relying on eyewitness identification. Problems with misidentification can include:
- The viewer being distracted at the time
- The viewer getting a poor/partial view of the incident
- Faulty memory, especially after a lot of time has elapsed
- Memory being led astray by suggestive questioning when testifying
According to the Innocence Project, mistaken identification contributed to about 69% of more than 375 wrongful convictions overturned by post-conviction DNA evidence. That means that almost 7 in 10 eyewitnesses were mistaken or wrongfully identified an innocent person.
In a police lineup, the police may include a handful of people who do not match the description of the suspect. The eyewitness may mistakenly believe that one of the people in the lineup has to be the suspect, which can lead them to point to the one person who most closely matches the description, even if they are not very confident in their choice.
Over time, the eyewitness may lose a clear picture of what the subject looked like; memory can start to fade in a matter of mere hours. The police may also use hints and suggestive language to try and steer the witness to picking a particular person that the police already suspect. For example, when presenting the witness with a book of mug shots, the police could focus on one page or one picture, which would bias the witness's choice.
Many people do not understand how someone could confess to a crime they did not commit. However, the stress of going through the criminal justice system combined with coercive tactics of the police can break even the strongest of individuals. The use of forensic science and DNA has overturned more than 360 wrongful convictions that included a false or forced confession. Ways law enforcement can pressure suspects to admit to a crime they did not commit include:
- Use of physical force
- Threats against the suspect or the suspect's family
- Exploiting suspects with limited mental capacity
- Coercion through deprivation of sleep, food, or water
Juries may hear from informants who claim that the defendant admitted to the crime. A jury may be more likely to believe the informant before they find out about the informant's motivations. A jailhouse informant may be offered a reduced sentence in exchange for informing on the defendant. Police may also promise leniency to confidential informants in their own criminal cases in exchange for testifying against another defendant.
The Sixth Amendment also guarantees criminal defendants the right to a public trial with an impartial jury. Unfortunately, defendants do not always receive a fair trial. State prosecutors often have access to a lot of evidence in criminal cases, and may have exculpatory evidence—evidence that would suggest that the defendant is innocent. If the prosecutor withholds that information, the defendant may not be able to get a fair trial.