My possibly-incomplete understanding is: * there was enough genetic evidence at several of the original crime scenes to establish one particular person was inv

My possibly-incomplete understanding is: * there was enough genetic evidence at several of the original crime scenes to establish one particular person was involved * after this suspect came to their attention, apparently via DNA on genealogy sites, they surveilled his home and collected additional 'left-behind' DNA – perhaps from his trash, or a haircut, etc? – to confirm a match with the older crime-scene evidence