This makes no sense to me because if all her pictures of her precious child were on a "hard drive" you would think she would down load them on to a disc, print them etc.
That would be an innocent person's instinct.
Something's really not right about these people - from the obvious to what we dont' know.
Even assuming they had the CD burner and CDs, four years' worth could potentially take a long time to burn to disc.
print them etc.
That would take even more time, and I'd bet any prints they would get from their own printer would be well short of keepsake quality.
Time is in very short supply when a murder investigation is cranking up.
Again, it's the only good excuse I can come up with for their being 'freaked-out' about the cops conficating their hard drive. I have no idea whether it's the actual reason.