But that's just the thing: AS a general rule, you don't. Innocent people do not "lawyer up" typically. (Sometimes even the guilty don't). In my experience, as an attorney whose law partner is a criminal defense lawyer, innocent people tend to immediately talk, give DNA, give their alibis, etc. It's not until they realize they are being targeted by police or arrested that they realize they should probably get counsel. And this goes for very intelligent people as well.
But I guess that's neither here nor there, as this guy hasn't lawyered up yet, right? And I see that some are saying he's been quiet but do we know that? IF he's not cooperating and talking, that would be a red flag to me. Because it;s not about what we should do. It's about what people tend to do. It's about profiling. (Or trying to!)