I think if I had to go into LE I'd be so stressed out I'd be confessing to the time I stole a candy bar with my friend when we were kids and rode off on our bicycles. I'd probably tell them more than they wanted to know. But I'm at core, an essentially honest person. Not perfect, but I come from an honest family. It just is.
Others are not essentially honest. And unfortunately, I think this is the case with NK. Not just because she had an affair with a married man. But because when she
went to LE, likely after a coworker had informed her the police knew about her, she had cleaned her text history, etc. So cooperation was a pretense. Was she there because she cared about CW's wife and kids? Meh, not from what we've now seen on the doc dump. She went to cover her own butt, she was looking out to protect NK.
LE saw right through her, they can spot a liar and she lied to them. We know she lied in her TV interview too (was she paid for that?). We know because the doc dump outed her. And I think that was done by LE on purpose, to prevent NK from profiting from this tragedy, in which she was not an innocent bystander.
And IMO, CW and NK were in lust, not love. He doesn't even know what love is..