"evidencia" is for the time being a false friend, except in the medical field, although this fact is rapidly changing.
In Spanish, "evidencia" refers to something that is obvious, immediately apparent. Using "evidencia" to refer to individual pieces of evidence used to support a theory that is *not* obvious can really muddy communication.
Don't have time to edit the text but I'd say "pruebas" for evidence in a trial, and "indicios" or "pistas" or even "datos" in other contexts.
I came across the phrases:
"of colours, there are evidences of great ingenuity" -- H. E. Dudeney, Amusements in Mathematics
"In all this, it may be said, the fact of evolution has been taken for granted, but what are the evidences? Perhaps it should be frankly" -- J. A. Thomson, The Outline of Science
"Other evidences of the origin of the barrel-organ are not wanting." -- Encyclopedia Britannica, 11th Ed. From "Barrel-Organ"
- I marked the noun as possibly countable. --Ivan Štambuk 10:29, 18 June 2010 (UTC)
There's a nice discussion on the correctness of the word "evidences" on the English Stack Exchange. Their conclusion, based on the Oxford English Dictionary, is that "evidences" is an obsolete word.