I believe the Orange County District Attorney’s office is among the LEO units making use of some of the latest DNA tools.
A suspect is NOT charged based solely on relationships identified by online genealogy and dna sites.
My sister did Ancestry DNA. Via their cousin autosomal matching, a few people have contacted her.
We have estensive traditional (non-DNA) records, and every DNA cousin match checks out.
One advanced crime solving method, is using the Gedmatch online DNA database.
Another toolis using quick DNA testing analysis, like the military uses with battlefield casualties.
https://orangecountytribune.com/2017/10/31/man-killed-by-hb-police-was-a-murderer/
Orange County case solved using latest DNA methods