I've read up quite a bit on the turnaround for DNA searches and data to come back, from what I gather it could take months or even years. By that I mean if the DNA doesn't immediately match a person, and they (LE, FBI, etc.). resort to links to relatives, it could take months or even years. Parabon doesn't take too long, from what I gather, it just costs some money up front. The forensic genealogy stuff can take many months or even years.
I watched videos about the GSK last night, including interviews with some of the investigators. They linked GSK to a cousin who had submitted their DNA, and the link was a relative or relatives they both were related to via a marriage in the 1800's. Figure GSK was born in the 40's, so this could have been a great or maybe great-great set of grandparents, I'm speculating. Retired detective Holes said it took over four months, but just imagine the resources poured into that case once they had a familial link, some names, names of ancestors, etc. Four months, because they knew they were definitely on the trail of one of the most notorious criminals in American history, and there was a chance he was still alive. Exhaustive, painstaking work. Walking through cemeteries, collaborating with genealogy experts, etc. Figure in IRS and social security records, that sort of thing, and sure it can speed things up a bit, but both have been around for only so long.
The genealogy research I've done on some of my ancestors was painstaking, and I'm probably lucky I found much at all, versus a lot of people who try it. Things can get muddled quite a bit prior to 1930. Stands to reason why LE are turning to experts in these cases, now that the DNA tech has advanced so much in recent years.
I hope they have usable DNA in the Delphi case. I don't think LE have a clue who did it, however I do believe something has changed in recent months, the PC from February was kind of weak, I thought. Now with their new "direction" I wonder what information they're focusing on.
Even if they have DNA and it's being processed, examined, chased down, etc., it could take some time to flesh out. I think two things are key to the puzzle, 1. DNA, and 2. A credible tip which leads to a prime suspect.
JMO
-FD