DNA Doesn’t Mean Guilty

When it comes to true crime cases having DNA evidence is often treated as the holy grail of evidence. If someone’s DNA is at the scene of the crime, then they must have committed the crime, right? Wrong.

Generally, evidence is classified into two categories: circumstantial and direct. Circumstantial evidence requires jurors to make inferences about the information presented to them whereas direct evidence doesn’t require any inference from the jurors. I feel it’s important to recap the two types of evidence because people often wrongly make the assumption that circumstantial evidence is weaker than direct evidence, which isn’t necessarily true.

It’s also important to note that there is no legal distinction between direct and circumstantial evidence as far as the court proceedings go, but jurors must be confident that the accused committed the crime beyond a reasonable doubt.

Direct evidence is the testimony of a witness who was present for the crime and used their senses to determine what happened. This means the witness saw, heard or touched the attacker directly and no inference is needed. Physical direct evidence includes video or audio recordings where the crime can clearly be seen to be happening.

Of course, video evidence is extremely strong and makes for good direct evidence but this isn’t true of all direct evidence. The court requires testifying witnesses to take an oath declaring their testimony is honest. This truth is presumed, but some witnesses will be more reliable than others. Someone unconnected to the case who has no prior record of criminal activity is likely to be trusted by the jury more than say, the defendant's mom or brother. Additionally, human memory is famously faulty, especially when you are exposed to traumatizing events which adds more unreliability into the mix.

Circumstantial evidence relies heavily on inductive reasoning and inference. For example, let’s explore a fictional assault case. In this scenario, a man was attacked on a street corner, and you were on the next street. You didn’t see the attack, but you did see a man walk down the street you were on carrying a knife. It’s reasonable for you to infer from this that you saw the attacker, but this isn’t direct evidence because you didn’t see the attack so you can’t confirm that the man you saw actually conducted the attack.

There is lots of evidence that would fit into this category, and DNA is one of them. Although DNA and other evidence that fits into the category of ‘scientific’ is often held in high regard, it can only be used to infer someone’s presence at the scene of the crime, not prove it directly.

Now we’ve brushed up on the types of evidence we can look at why DNA evidence isn’t always the ‘smoking gun’ it’s made out to be.

On 29 November 2012, San Jose millionaire Raveesh Kumra was killed during a robbery of his 7000-square foot mansion. A group of men entered the mansion and found Kumra watching CNN in the living room, where they gagged him. Kumra died of asphyxiation after being gagged with packaging tape which covered his nose and mouth.

The men also found Kumra’s partner Harinder asleep in an upstairs bedroom and dragged her down to be with Raveesh. She was hit on the mouth as well as blindfolded with her hands tied behind her back. The men stole cash, jewelry, and rare coins and left.

Once the men had left, Harinder called 911 and requested the police and paramedics. DNA was found under Kumra’s fingernails and was found to match Lukis Anderson.

Anderson was an alcoholic who’d been in trouble with the law previously, being convicted of felony robbery. He was arrested by police three weeks later, charged him with murder, he Anderson and waited five months in prison awaiting trial.

Anderson didn’t remember committing the crime, but he told his public defender Kelley Kulick “I drink a lot”…”Maybe I did do it”. Kulick got copies of Anderson’s medical records, hoping that his medical history might result in a more lenient sentence from the judge. What she found was surprising.

On the night of the murder, Anderson was actually in hospital after having consumed the equivalent of 21 beers. He was kept in the hospital for 12 hours, not being released until the next day. The whole crime had occurred while he was drunk and sleeping in a hospital bed. That’s why he couldn’t remember it, he wasn’t there, and he was so drunk he has very little memory of the night. He had an airtight alibi.

Kulick brought her findings to the court and the case against Anderson was dropped. So how did this happen? How did an innocent man’s DNA end up at the crime scene? Transfer DNA.

It turns out that one of the paramedics tending to Kumra also picked up Anderson earlier in the night. The paramedic had transferred Anderson’s DNA onto Kumra and that’s how he was placed at the crime.

It’s certainly possible that without this revelation Anderson could have been found guilty and received a life sentence, and possibly even the death penalty. Not only did DNA evidence place him at the scene, but there was circumstantial evidence too; he had committed felony robbery in the past and was in the San Jose area at the time of the crime. He also had no alibi.

This isn’t to say that forensic scientists aren’t aware of transfer DNA and try to mitigate it, they are, but mistake still happen. DNA evidence can form a significant part of the picture when it comes to crimes, but it’s just that, one piece of the puzzle. DNA does not always mean guilty.

Reader, writer, addicted to Wagamama. I write about things I enjoy - Science, technology, gaming, reading, culture.

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