Agency SOP's can be a problem. Within a 50 mile radius and depending on which department you have several different SOP's (Alabama) that would or would not allow you to do that or some modified version of it. Also depended upon if your were uniformed patrol officer or detective or task force,etc. Point is their is nothing illegal about it at all and it is done all the time, with and without lawyers present.

The REID organization developed a special program just for this situation called the field interview method. This is more patrol/state trooper oriented /drug interdiction operations and although I have not been to it alot of Trooper organizations use it, at least in the south. It has a lot more of the behavioral analysis in it, again this is second hand information.

I am straying from the point of this thread so I will shut up here with this final point. From my viewpoint the interviewing/interrogation of POW's etc. from and Intel point of view is more along the lines of a negotiation for information than a standard LE type interview. However working an informant for information seems to me to be almost the same, again when I was "working" my snitches and my bitches (hookers) I was after information so I could nail the suspect even if he did not confess in the interview. And I was willing to negotiate for that with my CI's. Trade Small fish for Big fish.