One of these things is not like the others.One of these things just doesn't belong.

Well, I have three theories. Hear me out:

1. Shulz - because he's not American

2. Joe Friday - because he's not military

3. Tim Conway - because he's an officer, not enlisted (or a Sergeant)

Please let me know how I did.

How do you know Friday isn't in CID?

LOL, Yes, I know that he WAS a Drill Instructor before he went LAPD, but he's clearly LAPD in that lineup.

One more: Sergeant O'Roarke is from the 1800s and by all outward observations should be dead by now.

13 minutes from submission to being featured. My best time evar!

Yes, that is really good, especially for a nonstandard template.

When are you going to publish the answer?

Rank. They are all Sergeants except the bottom one who is an Ensign in the NAVY.

Good.