Answer:
According to HIstory.com
Faced with an Aztec revolt against their rule, forces under the Spanish conquistador Hernan Cortes fight their way out of Tenochtitlan at heavy cost. Known to the Spanish as La Noche Triste, or “the Night of Sadness,” many soldiers drowned in Lake Texcoco when the vessel carrying them and Aztec treasures hoarded by CortÝs sank. Montezuma II, the Aztec emperor who had become merely a subject of Cortes in the previous year, was also killed during the struggle; by the Aztecs or the Spanish, it is not known
I believe the answer is: <span> preservation of evidence.
</span><span> preservation of evidence is critically important because the genetic Trace or fingerprints that left on the evidence could be easily erased.
When such evidence is erased, the justice department wouldn't have sufficient proof when they are prosecuting the suspects.
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