There is no legal or evidential principle which states that a jury cannot consider a case which depends solely on DNA evidence left on an object by a defendant at a crime scene.
In June 2016, as Ms. Carr entered her car and prepared to drive away, a man opened the driver's door and a struggle ensued. She was able to get a general look at him (but not enough to identify him at a later identification parade). The victim was dragged out of her car by the man who then escaped with her gold necklace. He appeared to have an accomplice. A DNA analysis was made of the exterior driver's door handle, and revealed the defendant was the single major contributor and there was at least one minor contributor. The scientist undertaking the analysis stated that the single major contributor's DNA was more likely due to the person touching the door handle, rather than secondary transfer.
At trial, the Defendant advanced a submission of no case to answer, stating that no reasonable jury could properly convict on the available evidence. The trial judge rejected that submission and said that the totality of the evidence in the present case (including the location of the defendant's address) was sufficient for consideration by a jury. The defendant was found guilty after trial.
The defendant appealed and the Court reflected on a review of case law they had recently undertaken concerning DNA evidence.
The previous position in Bryon  EWCA Crim 997 was not correct. The Court in Bryon had stated that where a defendant's dna on a moveable object at the scene was the only dna found, there should be some further supporting evidence against that defendant for the case to be left to the jury. The Court here stressed that this was an obiter observation and was not the basis of the judgment in that case.
The Court stated that there is no legal or evidential principle which states that a jury cannot consider a case which depends solely on DNA evidence left on an object by a defendant at the scene of a crime, provided the match probability is very high. However, it would depend on the facts in each case. Questions to consider would include whether the article with the DNA profile was associated with the offence itself, how moveable an item it was, whether the defendant advanced an explanation for the presence of their DNA on the item, whether there were other profiles found, and whether the defendant's profile was more likely caused by primary or secondary transfer.
13 March 2017