Evidence of what? Destroying evidence assumes he is guilty of a crime which there be evidence of. Our system is predicated on an assumption of innocence. The normal threshold to accuse is a "reasonable, articulable suspicion." This does not meet that criteria.
Well that's the thing with destroying evidence. If you destroyed it, it becomes harder (or impossible) to prove you did the crime. That's why it's not uncommon for people to be only charged with stuff like "obstruction of justice" rather than the actual crime they allegedly did.
> Our system is predicated on an assumption of innocence.
In theory. In practice, this is a hopelessly outdated supposition.
Destroying evidence or items believed to be evidence is a crime in itself, regardless of whether or not the original "evidence" or lack thereof pertains to a crime.