Neighbors never heard the jackhammer needed to bust up the concrete flooring to initially get a hole big enough for burying the body? Did she hire someone to do the deed of actual burying? She doesn’t look too hand with heavy equipment needed and carrying in bags of cement.
“handy”
A mass of hardened concrete doesn't sound like it was a professional job designed to be the perfect crime. More like she threw the body in a corner and dumped wet concrete over it hoping nobody would notice. I could be wrong but that would be my guess.