I just spent half an hour reviewing everything I could find online.
The only evidence of any sort appears to have been the previous altercation.
The stab wounds themselves could actually be evidence if they can match (or closely match) a knife. And the location of the wounds might be telling of someone with training and/or on offense or defense. If the knife had the serrated top edge (like a combat knife), it would leave some tell tale wounds.
That said, the evidence would be circumstantial unless they matched DNA to the Soldiers equipment or visa versa.
Not enough to convict. The dead guy was beaten and stabbed. Did the Navy man have any injuries to his hands/body giving any indication he'd beaten or stabbed anyone? Any wounds himself from the dead man fighting back? He appears to have no facial injuries in the mug shots. Anything on his arms/legs showing defense against blows, given that a SEAL (if he is actually a SEAL, it's not really confirmed, just inferred in the article) would likely be able to defend against face/body shots better than most.