He's very frustrated because Rosie is the most important thing in his life.

It's conceivable that the D.A. could find that there is not enough evidence. It would be unusual, but this is an unusual case.

The fact that someone might have a marginal motive to get rid of someone doesn't mean they killed them.

What do they have to lose by interviewing the suspect? Either he's going to bury himself or exonerate himself.

We want the LAPD to investigate Robert Blake. The more they investigate, the more they'll find out he didn't do it.

The civil case is coming up next month and they're trying to dirty (him) up in anticipation of that case.