In Swedish, evidence is countable. So ett bevis means ’one piece of evidence’ and is used in the plural to mean ’evidence’. It’s the same with möbler which means ’furniture, and en möbel is ’one piece of furniture’.
I think bevis probably means the same as we say in Dutch: bewijs. Wich means: proof.
But we use that word also for documents that proof something such as in 'rij-bewijs', which is drivers license. So 'bevis' probably can also be used as 'licence' i guess.