NRS 52.245: Admissibility of duplicates.

1. In addition to the situations governed by subsection 2, a duplicate is admissible to the same extent as an original unless:

(a) A genuine question is raised as to the authenticity of the original; or

(b) In the circumstances it would be unfair to admit the duplicate in lieu of the original.

2. Except as otherwise provided in NRS 52.247, a duplicate is admissible to the same extent as an original if the person or office having custody of the original was authorized to destroy the original after preparing a duplicate, and in fact did so.