The Biblical Standard.
If a false witness rise up against any man to testify against him that which is wrong; Then both the men, between whom the controversy is, shall stand before the LORD, before the priests and the judges, which shall be in those days; And the judges shall make diligent inquisition: and, behold, if the witness be a false witness, and hath testified falsely against his brother; Then shall ye do unto him, as he had thought to have done unto his brother:
so shalt thou put the evil away from among you. And those which remain shall hear, and fear, and shall henceforth commit no more any such evil among you. (Deuteronomy 19: 15-20)
In other words, does the presence of a rapist's DNA, properly tested and testified to by an expert witness meet the Biblical standard of "witness"? Likewise, does the presence of fibers from a murder victim's clothing, discovered in the automobile trunk of the alleged murderer, and properly tested and testified to by an expert witness qualify as a Biblical "witness"? Same for fingerprints, and other scientifically valid forensic evidence.
I am inclined to say that this type of scientific evidence does qualify as meeting that Scriptural standard, but recognizing that these tests did not exist in Moses' day I am disinclined to be more definitive in my answer. For example, I do not know whether I could vote for the death penalty in a case that hinged entirely on this type of evidence without supporting eye witness testimony. I do believe that I could find a person guilty, and sentence them to life without parole, but don't know if I could actually vote to have that person executed.
Your thoughts? (Or better yet, Scripture that I may have overlooked.)