Yeah, I get the idea of using an informant who is linked to the person you're trying to catch. It makes sense as a way of gathering evidence against more serious criminals. It's a grey area, but broadly speaking I think it's ethically ok.
What I'm having a problem with from an ethical point of view is taking someone who just happens to have been arrested for an unrelated crime, and coercing them into doing undercover police work for you. This person hasn't been to trial yet, might be completely innocent, and is going to be placed into a potentially dangerous and definitely stressful situation.
That's why I was shocked by the article - it makes it sound as though Gideon didn't know Frank. Maybe the author just glossed over some link between them.
What are the safeguards around this? To give an absurd example, what's stopping the police from arresting someone for, say, taking a piss in a back alley, and then sending them in to infiltrate a violent criminal gang?
> Like, why would the police entrust something like this to an untrained, highly stressed, and unreliable person when they could just use a plain-clothes officer?
How many undercover gigs can you do before people start to catch on? Also, whoever you want to target may already know the informant and have some implicit level of trust in them.