How long have they been looking at this guy? They are claiming they can match DNA at the crime scene, pretty fast comparison, unlike TV, it takes a little time to do that so when was this comparison done? When did they obtain a DNA sample of this guy to compare it to? Lots of questions here.
“When did they obtain a DNA sample of this guy to compare it to?”
it’s pretty obvious that was why the FBI was surveilling this guy for five days before they arrested him, namely to snag a DNA sample via a tossed fast food container or similar ... cops do that all the time ...
AND DNA matching is orders of magnitude faster than in the olden days because many State police, the Feds and many major cities now have modern DNA processing equipment ...
and given that the FBI was involved, they probably had a match done in hours after the comparison sample was obtained ...probably flew it to their main DNA lab on one of their jets ...