DNA is only one piece of evidence...they still need to try to place him at crime scene, near the arena, etc, somewhere Morgan was known to be, make sure he was not out of town, check alibi as best as possible. At least one "Cold Case Files" I watched had a DNA match from a coffee cup just the start of putting a case together. First thing they needed to rule out was any chance that the killer knew the victim and could have been in a consensual relationship. They then moved on to determining where he was that night. So it is not just DNA= entire case.
I'm sorry and I.m not trying to rude. Dna does not work in the format restriction for all DNA. This would depend on the type of DNA found Some are stronger than others and some seal the fate of the perp.. How it was found and what was found.. Let say for example semen, this put him there, put a lot of crimes things there. So there's no need do all alibi and etc. Unless you want to string along a lie of the perp and make them look bad in the court room.
Now if they find a shoe. This would be what your talking about.. that's is called a cat and mouse case. That what I like to call them some, call them "Oj" cases. Yes I have a sense of humor.
But if they found semen. That's not a cat & mouse case. That we lawyers call check mate, because its very to beat in the court and also a dead body found please note, finding a dead body needs something like dna to damn(convict) the perp for the DP(death penalty) if not only life in prision. But to my points,.. Semen will put him there with the person, time don't matter, His/her albi don't matter. All that is , just stringing along differ methods for scenario really. Defeating his/.her doubt or innocence if you will.
Please note im not saying this is what they found or your wrong.. I'm jus expanding on your quote to straighten it out ,so its more fair judged.
There certain type of DNA some more damning than others.. Btw his lawyer he has is very ,very good, the more evidence you have in public, the better for the accused chances to beat it . So it best omit some things from a LE stand point.