I know there aren't many lawyers here but...;-)

I was wondering about the legality of say a freelance news photog, taking video of say a crime scene, with emergency personnel around (police, fire, emt etc) a defendant being arrested and later selling this as royalty free stock footage. There are clear shots of faces etc,

In a news situation you wouldn't need releases, but what about re-sale later? Say the person arrested was charged with, I don't know, say Domestic violence, and the producer who purchased the royalty free clip used it in a video about murderers, would they be liable for casting the detainee in a "false light?"

* and no, I did not take such footage.

Just a layman's answer: if it feels wrong, it is more than likely wrong.

And it does feel wrong... Let's say my girlfriend called the cops and I get arrested - men get easily arrested in such situations. Later the evidence shows that I was innocent and she caused the whole fight (say she came home drunk from a party).

You filmed that, sold it as royalty free stock footage and some day I watch myself being arrested, in a documentary about domestic violence on CNN. You bet I'll find out who sold that footage and drag you to court! Of course this is all hypothetical and CNN knows better, but I think this pretty much answers your question.

I know there aren't many lawyers here but...;-)

I was wondering about the legality of say a freelance news photog, taking video of say a crime scene, with emergency personnel around (police, fire, emt etc) a defendant being arrested and later selling this as royalty free stock footage. There are clear shots of faces etc,

In a news situation you wouldn't need releases, but what about re-sale later? Say the person arrested was charged with, I don't know, say Domestic violence, and the producer who purchased the royalty free clip used it in a video about murderers, would they be liable for casting the detainee in a "false light?"

* and no, I did not take such footage.
The short answer is: yes, there is potential false-light defamation liability. There are additional concerns with respect to commercial appropriation of likeness (the laws for which vary state-by-state) and other invasion of privacy torts.