Wait a minute. I had a lightbulb moment. (what constitutes one for me anyway.)
He confessed to leaving the kids home alone the same day that Hassani went missing. Seems pretty convenient, doesn't it?
"Yes, Officer, I know he wasn't on the banks surveillance...that's um, uh, becuase, I left him at home...yeah, that's it. He was alive and well at that time, but I did leave him home alone with his much younger sister."
Just saying, isn't this kind of like the guy that gets hauled in for beating his ex to death and tells the prosecutors, "Yeah, I hit her, but that was all I did." Admit something minor so you seem honest and maybe they don't look at you as hard for the big crime.