On November 29, 2012, Raveesh Kumar was killed during the robbery of his California home. He was tied up and gagged by the robbers, and suffocated because the duct tape covered his nose and mouth. Three weeks later, Lukis Anderson was charged with the murder. His DNA had been found underneath Kumar’s fingernails.
Anderson was a homeless man who usually stayed around San Jose. His DNA was in the databank because he had previously been convicted of a felony in California. What’s more, Anderson had been convicted of a felony robbery. After his arrest, he told his lawyer that he had no idea who the deceased was, but that he drank a lot, so he wasn’t sure what happened.
Anderson’s lawyer got copies of his medical records because she thought that his medical history might help him get a more lenient sentence. When she received the records, she realized that she had hit the jackpot: the records showed that Anderson had been admitted to the hospital on November 29, having drunk the equivalent of 21 beers, and was not discharged until the next morning. It was impossible for him to have committed the murder – he was in the hospital when it happened. He had an airtight alibi.
Once this material was presented to prosecutors, the charge against Anderson was dropped. It turned out that Kumar had been in the same ambulance and dealt with the same paramedics on the same day that Anderson had. No one knows exactly how the DNA transfer happened. It is possible that it was transferred on the clothes of the paramedic, or that the two men shared the same finger pulse oximeter. But for the good luck that the records existed and the good work of his lawyer, Anderson could easily have been convicted of Kumar’s murder.
The scientific community only has a basic understanding of DNA deposition (how and when DNA is transferred). In 2017, the Supreme Court of Canada was poised to deal with dueling experts on this exact issue in a case called R. v. Awer, but decided the appeal on other grounds. In Awer, there was a significant difference of opinion between the Crown expert and the defence expert as to whether the DNA in that case could have been transferred while it was dry, or only while it was wet. One opinion meant conviction, but the other opened up the possibility for an acquittal.
Defence lawyers need to be prepared to understand and deal with the factors experts still don’t know when it comes to the use of DNA in the courtroom. The question of how someone’s DNA got where it did is crucial to a criminal trial, and experts can and do go beyond their expertise in closing off possibilities of indirect transfer of DNA or other mechanisms of innocent transfer. While DNA can be a great tool to prove that someone was wrongly convicted, it can also easily be misinterpreted and lead to wrongful convictions, as almost happened in the case of Lukis Anderson.