FamilyTreeDNA, an early pioneer of the rapidly growing market for consumer genetic testing, confirmed late Thursday that it has granted the Federal Bureau of Investigation access to its vast trove of nearly 2 million genetic profiles. The arrangement was first reported by BuzzFeed News.
I was interested in doing this through Ancestry.com but heard these types of firms were keeping a database of the samples you provide. Once I found that out, I said no thanks. Not that I have anything to hide. But they should not be keeping this without my consent or just in general.
I had the same thought as you.
I watched a documentary on the golden state killer. They had the killer's DNA but it wasn't in the data bank; but a distant relative of his was in the data bank. This led the investigators to narrow the suspects and find the killer. It's amazing what they can now do with DNA.