mere said:
What you are saying is that if a victim is buried it is not likely they would ever be found?
No, I am not saying that at all. I only mean that most bodies of John and Jane Does are found on the surface, rather than by digging up a grave.
While burial may hide the victim from the casual passer by, it does preserve the remains better, as it keeps preditors and the elements from scattering them. The problem is that after only a short time, the gravesite looks pretty much like all the surrounding land. This makes it extremely hard to find. Those John and Jane Does who are found in shallow graves are usually found "accidentally" by workers digging a utility trench, or foundation.
There are methods which can be used to locate graves, such as aerial infrared photography, cadaver dogs, in-ground radar, dowsing, and probing. Sometimes a grave can be seen visually as a sunken area, a mound, or a difference in vegetation. These methods, in and of themselves, usually are not considered sufficient evidence necessary to obtain a search warrant.
Such methods give indications of anomalies which MIGHT be a grave, or might be something else. Unfortunately, sometimes follow-up methods used to try to confirm a possible grave are not always reliable.
As an example, land developers and builders might be confronted by persons who claim that there is an old unmarked cemetery on the property. The developer must conduct tests to confirm whether or not there are graves in the area where he wishes to dig or build. A standard practice is to hire an archaeoligist with a bulldozer to scrape the surface of the land and look for "grave shafts". The theory is that when the grave was dug, a disturbance was created, and the soil which is put back is of different color or substance from soil near the surface. Thus, when peeling back the top soil, a clear indication of a rectangular grave shaft should be evident.
This works sometimes, but not always. Recently, when speaking with an Archaeologist about this subject, he mentioned a case in the past year where in-ground radar indicated a strong anomaly. Probing indicated a possible coffin about four or five feet down. During the entire dig, there was no evidence of any stratification of soil and no indication that there was any kind of a "grave shaft". Upon hitting what appeared to be a hollow sounding coffin, they found a box which had a plastic bag attatched with duct tape, and inside the bag was a handwritten note.
The note was dated 1995, and it stated that this was the body of a pet dog. It requested that, if located, it be re-buried somewhere else. So, here was a case where the grave had been there for just under ten years, but there was absolutely no evidence of the grave until they actually dug up the coffin.
The state of preservation of a body when exhumed from a grave will vary considerably, depending on many factors. First and formost is the condition of the grave itself - such as type of soil and presence or absence of water. The depth of the grave, presence or absence of trees or other plants, presence of burrowing animals, type of insects present, etc all have an effect on the body. When body is wrapped in a carpet, tarp, or blanket, or if it is in a container of some type, remains and possible evidence are better preserved.
An interesting historical commentary on this can be found in the report of Dr. Samuel Weaver to the Governor of Pennsylvania upon the removal of Union Soldiers from Gettysburg battlefield and hospital graves to the new (in 1863) Soldiers Cemetery in Gettysburg. Samuel Weaver supervised all of the grave openings and reinterrments personally. He made attempts to identify some 5,098 Union soldiers, as well as many Confederate soldiers, who were usually reburied in their same battlefield grave when discovered. His report includes condition of many bodies, descriptions of items found, etc. He notes that some bodies were remarkably well preserved and recognizable, while in the same amount of time, others were completely skeletonized.
In regard to the Lyon Sisters, I feel very strongly that the case can still be solved, and have hope that the girls will some day be found.