S&BBM
You said, "
At best, it leads to a family group."
And this is just not correct.
At best infers that there is a large pool of candidates and a certain unreliability. Sometimes it leads to only one possible person. From your own link:
We got lucky on Hawkins: A direct family member had uploaded a genetic DNA profile to a public open-source database.
By Leighton D’Antoni Assistant Criminal District Attorney in Dallas County Forensic investigative genetic genealogy (abbreviated FIGG, IGG, or FGG) is a groundbreaking tool in the field of criminal…
www.tdcaa.com
This is exactly as I said--it depends on the matches and how much DNA they share with the unknown profile. The closer the matches, the fewer family members that will fit correctly in the puzzle sharing the correct amount of DNA with all the matches.
From your own link:
This list of genetic relatives, more commonly known as DNA matches, can range from close (e.g., sibling, parent–child) to distant (first cousins and beyond) relatives. The amount of DNA shared can then be used to compute probabilities for possible relationships to place DNA matches into predicted positions in the unknown individual’s family tree. Following this, documentary evidence, e.g., civil registration records (birth, marriage, death, etc.), plus other investigative evidence, can be used to build out the family trees of identified/verified DNA matches, typically beginning with identifying who the DNA match’s parents, grandparents, etc. are. As a family tree is built back through generations, a most recent common ancestor (MRCA) is searched for. This is an ancestor that both the unknown and the DNA match share and have both descended from. Building the family tree forwards in time from the MRCA(s) and filling in multiple branches of the tree to generate family networks, could lead to a potential identity of the unknown, or narrow it down to a group of brothers or sisters within a family.
Forensic Genetic Genealogy (FGG) has fast become a popular tool in criminal investigations since it first emerged in 2018. FGG is a novel investigatory tool that has been applied to hundreds of unresolved cold cases in the United States to generate ...
pmc.ncbi.nlm.nih.gov
This is the most common result--a group of siblings in one family. BK is the only known male sibling and lived by the crime scene--surely the focus would be on him, not a wider family group.
From your own link:
The genealogical research may lead to a possible candidate or candidates for the identity of the unknown. Multiple candidates may be suggested in cases where the genealogical research leads to a family of multiple brothers or multiple sisters. The genealogical research cannot determine which one of the brothers/sisters the unknown is suggested to be, however biographic information such as age, known addresses at the time of the crime, etc. may assist in narrowing it down to one brother/sister.
Candidate or candidates, one brother/one sister. It depends on the matches and sibling group.
Forensic Genetic Genealogy (FGG) has fast become a popular tool in criminal investigations since it first emerged in 2018. FGG is a novel investigatory tool that has been applied to hundreds of unresolved cold cases in the United States to generate ...
pmc.ncbi.nlm.nih.gov
Depending on the matches, IGG can be inherently self-checking. If you pinpoint an individual or sibling group, the DNA of the unknown must be consistently correct in that spot with all the matches and the amount of shared DNA.
JMO