My take on the construction site: Jmo
I've been a project mgmt consultant now for 40 years. My clients are developers, owners, and GC's on large commercial construction projects located all over the country.
In commercial work, there are Site Work / Utility contractors, and then there are Landscape contractors. A Site Work /Utility contractor is the first sub on site. They handle mass excavation and grading, stripping topsoil, cut and fill, haul off /haul in, detention pond construction, entrance Rd construction, and undg untilities (storm, sanitary, & water, - less often gas or power). Sometime they are even responsible for the initial tree clearing and grinding (or they'll maybe sub that work to another sub)
Landscape contractors on the other hand do fine grading. They create berms. They smooth things out. They are just about the last subcontractor on the site. For the most part, they plant trees, shrubs, and sod, and work together with separate landscape lighting (LV) and irrigation crews. This work generally happens after the curb/gutter and sidewalks have been put place.
From what I can tell online, BM's company was definitely a landscape company, and not a site work /utility company. That said, unless he was real small time, he certainly would've had equipment capable of doing small to medium size (residential size) excavation and fill projects (i.e. excavation for a basement walls, foundation walls, deep piers, and pad grading), but not large site clearing, mass excavation/grading and utilities. For that you'd need mass excavators, big scrapers, dozers, loaders, and tons of trucks
The size of project a given contractor could handle would pretty much depend on how much and what size equipment the company owned or leased (that and how much they could bond)
I do think it's conceivable that BM could have done some "site work / utility" type of work on that residential project (where he was maybe contracted to later do landscaping). Excavation and fill at this early stage (especially for deep fdtns, basement walls, fdtn walls, below- grade piers, etc.,) of a residential project can still be pretty deep, maybe as deep as 10-12 feet.
If he buried something very deep, he likely covered the object with something before backfilling on top of it. This could potentially make the buried object very difficult to find (say, under a board or heavy plastic, covered by 12' of compacted dirt). This foundation or foundation wall backfill work would've happened WAY before any under-slab plumbing, under-slab or in-slab elect rough-in, mesh, and moisture barrier type inspections which typically happen just prior to a slab-on-grade placement/pour (all those things are in the sub grade).
I don't remember a lot from the several videos and stills of the investigation at the construction site that I saw, but it seemed to me that even in the areas where LE saw-cut the slab-on-grade, investigators weren't ever looking deep (at least not very deep). In fact, they were digging shallow, and even sifting. I never understood that.
Idk what ground penetrating radar can pick up (how deep and what materials and densities it can possibly see through), or how it was used (or even if one was used) at that residential construction site. I just remember thinking, "You're not looking deep enough. She would be deep, not right below the slab, not in the sub grade"
I mention this because I think this case will be nearly impossible to prosecute w/o a body, which is why (IMO) the investigation is (and will continue to be) stuck in purgatory.
I think that the residential site is still a very logical place for LE to look for SM's remains. They just need to look deeper. If they do not look there again - because they think they've already looked there once - I think they may never find SM, and never solve this case. Jmo
