Total Speculation session here, no names:
Let's say hypothetically that person #1 has ties to a victim of a violent crime , but their itinerary and location information is unknown
and let's also say that person #2 has ties to the time and general location of the violent crime, but their ties to the victim are unknown
In addition to their physical differences, #2 has a significant additional attribute in their life that #1 does not have. Hypothetically, law enforcement may have indicated that their prime suspect has this particular attribute. But of the two, only #1 has the proven connection to the victim.
#1 and #2 work together
They both have spent time at a great distance away from their families, some even from their "attributes", who's to say that one of them during this period didn't learn something that the other wouldn't want a third party to know etc. Hypothetically, of course. Just conjecture.
(no, neither #1 nor #2 would be married to the victim, hypothetically of course)