As i understand they can't use the few biggest databases for genealogy tho. I hope they still find a match in the other databanks

(From 13 minute mark on)
One of the data banks LE uses has some data from other much larger genetic genealogy sites. People who test at the main genetic genealogy sites can upload their DNA data to one of the sites now used by LE.
This one LE site started out many years ago as just a regular GG site with some fancy tools and helpful ways to analyze data.
People would download their data from the other main sites to use these tools.
Then it became part of an LE data bank. Most people still kept their DNA at the site. But you had to opt in or out of the LE use of the data. Many people thought, hey if a relative of mine commits a crime, I am not protecting them so they left their DNA sample at the LE site.
And regular people still use this site to analyze their DNA. (I was just on this site the other day, helping a cousin analyze their DNA data.)
So say if you doing your DNA investigation at this one LE DNA site, you can see where the matches have come in terms of other DNA sites. You can see some of the family trees, and then you can hightail it over to those other sites and find more extensive trees for those matches. So you can kind of back door things a bit.
This LE site will give you family surnames, birth locations of ancestors, etc. So you can narrow it down right off the bat.
I used to do adoption searches, it is the same procedure LE uses for criminal investigation.