Reversal was required where the chain of custody of a DNA sample was not adequately established. Jimenez committed a bank robbery after arriving at the bank on a bicycle. A DOJ criminalist compared a sample of Jimenez’s DNA with a sample left on the abandoned bicycle handlebars. Three witnesses, the police sergeant, the chief investigating officer, and the criminalist, testified concerning the chain of custody of the reference sample. Read together as a whole, the testimony of the three failed to resolve key foundational issues about the chain of custody. The chain of custody amounted to nothing more than separate links that did not connect into a chain. The trial court’s overruling of Jimenez’s foundational objections to the admission of the reference sample and the criminalist’s comparison of it was an abuse of discretion. Based on the record, it cannot be said that the erroneous admission on an inadequate chain of custody was harmless beyond a reasonable doubt, and reversal was required.