Since you and steveP120 have brought up questions about LLW2 and RAW1,
I would like to ask you both and anyone else here to answer the question of:
WHY are there SOME CASES where someone has admitted to a crime and perhaps have even received LIFE in prison or the Death Penalty and then--later--either DNA evidence comes to light or stranger yet--a victim shows up--ALIVE!!!??
The invention of DNA technology has overturned or called into question a very small percent of murder convictions or even murder confessions (the Central Park Jogger case). Depending on how measured, these cases were a very small percent of convictions, likely far under 1% depending on how measured.
Even rarer than the 1% or so bad convictions, is the almost unheard of murder conviction for murder of a victim who later turned up alive. To be fair, there have been few no-body murder convictions. A no-body murder conviction would be required if the victim were still alive. There may have been one or two murder convictions in modern U.S. history when the victim turned up alive, but off the top of my head, I can't think of a single one.
More common are cases where someone runs away, decides to cut all contact with friends and family, and start a new life, often living on the street or on the edges of society. Often runaways cut off all contact with old friends and family because they know their families would not approve of their sexual and/or substance abuse lifestyle. Often people run away from debt collectors or from dysfunctional families.
Missing person cases often become murder cases, especially if the runaway was a victim of domestic violence or stalking. These may be the cases that you are thinking of. Perhaps a few thousand or so boyfriends, husbands and other shady associates of runaways get roughly questioned by the police and even accused of murdering the runaway, but as noted above, few of these made it to murder convictions without a body.
Because of the young age of the Lyon sisters, it's highly unlikely that they run away and were able to run away for more than a few days.
Custody disputes sometimes, but rarely lead to kidnapping with no death or physical harm to the children, but this does not appear to be the case with the Lyon sisters. As far as we know, there is no relative who thought the Lyon's parents were bad radio parents, who may kidnapped the children to what they thought was a better home. There was some speculation online that some (Texas?) Welch girl was one of the Lyon sisters, but this has been denied, and would be easy to prove or disprove.
While extremely rare, baby snatching to provide children for adoptive parents, who many or many not know the baby or toddler was kidnapped, has happened. Kidnapping a child who speaks for an adoptive problem has the obvious problems that they can talk, and will likely talk about being kidnapped sooner or later even if threatened or brainwashed; this almost never happens.
While everyone would be happy if the Lyon sisters were still alive, and say turned up in France having been told that their parents died, unfortunately, this is the least likely outcome.
Sorry but the only comforting words I can offer are that Lloyd, if guilty, was such a screw-up, that the crime likely went wrong within minutes, before Lloyd accomplished many or any of his sexual goals.