It is so concerning to me how close those apartments are to that water and what a steep drop off it is with no fencing. Yikes :/ I wonder if he did tragically go in the water if the apartment complex will change that.
I'm sure LE know how the child got out of the apartment. His mom probably knows what she was doing around 9 PM and how it would have been possible for him to get out on his own. I wonder if the apartment complex has laundry and if so, where is it located? Perhaps she took him with her to do laundry so he wouldn't be left unsupervised if the apartment; the laundry room would probably not have a locked door, and he could have wandered outside while she was busy putting things in the washer. It would just take a second. This is all supposition, but just giving one scenario of how he may have escaped at that hour.
I am leaning toward a tragic accident of him wandering outside to the playground for a moment and then very sadly falling in the water. A part of me does wonder about an opportunistic abduction - I feel that is more unlikely but I guess in that case, there is a chance he'd still be alive. Someone would have had to just happen to be at that playground at the precise right time which I feel is definitely possible but maybe not probable. MOO.
Very sad all the way around.