It's relevant though. Missing information is just as important as provided information when it comes to the law. That's what they mean when they say the whole truth.

If Officer A arrests you for a DUI and speeding on Day X...the actions of Officer B on Day Y for a separate DUI case is irrelevant.

The "missing information" as you put it, is related to a murder-for-hire trial that is separate from the Ulbricht-ran-Silk-Road trial.

Only if the missing evidence is exculpatory.