Destroying The Evidence - Again

Apparently the church in Sutherland Springs, TX where the recent shooting took place may be torn down. You can read about it here:

http://www.latimes.com/nation/la-na-texas-church-20171109-story.html

Why do we destroy the evidence of such crimes? Additional examples:

• Murrah Building wreckage in OKC
• World Trade Center wreckage
• Sandy Hook school + the alleged shooter's home

Because of such destruction the official stories can never be challenged.

Is that a good thing? I don't think so.