BOB GARFIELD: For most of law enforcement history what happened in the interrogation room stayed in the interrogation room. Only signed statements emerged. But police misconduct, jury suspicion and inexpensive technology have converged to make video recordings of interrogations common practice. Many states mandate video records, and prosecutors have found them to be both a check on police abuse and a powerful tool to impress jurors. Till now the US Justice Department has resisted, but a new policy now requires the FBI, the Drug Enforcement Administration and several other federal law enforcement agencies to videotape interrogations of criminal suspects, a large step in making the practice standard nationwide.

Jennifer Mnookin, a law professor at UCLA, says the argument for videotaped interrogations resonates with all sides of the legal process.

JENNIFER MNOOKIN:  If we videotape interrogations, then the prosecutors can see what the suspect acknowledged. So can the jury. So can the defense attorney. The suspect has to live with his or her words. It provides much better information to everybody.

BOB GARFIELD:  And if they are being coerced to make the confession, theoretically at least, that coercion will be evident on the tape, right?

JENNIFER MNOOKIN:  That's right, there’s two benefits. One is it will probably reduce that coercion, precisely because it’s being taped. And, if it does occur, well, everybody can see that too.

BOB GARFIELD:  Before we get to your concerns, though, I want to ask you about why the Justice Department has dragged its feet till now amid all sorts of criticism and controversy over decades.

JENNIFER MNOOKIN:  Many law enforcement officials, especially those who haven't had experience with the practice, are concerned that the interrogation techniques that they regularly use might come across as looking kind of unsavory or unfair or unreasonable. I think they’re also sometimes concerned that potential defendants and suspects will learn more about those interrogation techniques and perhaps become better at resisting them.

BOB GARFIELD:  I must say my experience is that when a government agency is concerned that one of its practices might be deemed by the public to be unfair or unreasonable, it's because the practice is [LAUGHS] unfair or unreasonable. Is the Justice Department hiding these tactics because they’re suspect to begin with?

JENNIFER MNOOKIN:  Well, I think there is some degree of controversy over the line between reasonable persuasion and coercion. So, for example, is it reasonable for the interrogator to intimate that they have evidence in the case that they don't actually have? On the one hand, if it gets somebody talking and telling the truth, it may be quite valuable. On the other hand, if it leads a suspect to think, wow, they have DNA, the DNA is gonna show that it isn’t me and I can get out of this situation by giving this interrogator what they want, it can lead to a false confession. So it is true that videotaping more of these interrogations may lead some courts to reconsider the limits of what counts as voluntary.

BOB GARFIELD:  One way of looking at this is that it is a categorical victory for truth in prosecution. But you have caveats.

JENNIFER MNOOKIN:  I do. First, it's important to say that, on balance, I do think that taping interrogations in their entirety is a good policy. It's also an interesting reform because it does have such substantial support from all sides of the adversarial process, and that’s quite unusual. Defense attorney organizations support it, and so do many prosecutors and many parts of law enforcement.

But I guess I have two significant concerns. One is to make sure that these interrogations are recorded in their entirety, that the police can't turn the video recorder on and off. If they are able to turn them on and off we don't know what happens off-camera, and that's a very significant concern. Most of the policies on this, including the new federal policy, do require that when videotaping occurs it occurs in its entirety. So let's just hope that they do adhere to that. The other concern is about the details of how we tape - what the camera shows, who we include in the frame. A researcher named Dan Lassiter at Ohio University and others have done a pretty remarkable series of studies. He finds that if you take the videotape only of the suspect, viewers are much more likely to think that the confession was voluntary and not coercive as compared to if you take the video from a perspective that shows both the interrogator and the suspect in the same frame.

BOB GARFIELD:  A-ha, pull back to reveal.

JENNIFER MNOOKIN:  Exactly! If you see the interrogator in the frame, as well, suddenly the interrogation process looks different. The federal policy does not mandate or even suggest anything in particular about camera perspective.

BOB GARFIELD:  Juries, because they watch so much television about the TV version of criminal justice –

JENNIFER MNOOKIN:  Mm-hmm. [AFFIRMATIVE]

BOB GARFIELD:  - expect to see video. Is this policy in the name of more transparency or is it in the name of giving jurors what they think they deserve?

JENNIFER MNOOKIN:  I think it’s a little bit of both, to be honest. I am not at all convinced that in the ordinary course of things juries or, for that matter, anybody is necessarily going to be all that good at telling apart true confessions and false confessions just by watching them. We do know certain red flags that may be associated with false confessions. In many of the known false confession cases, interrogations were unusually long. But, at the same time, lots of true confessions may come after long interrogations. We may also sometimes see the interrogator feeding information to the suspect but, again, that kind of feeding probably takes place in lots of true confessions too. And so, we get these confessions on camera but that doesn't necessarily mean that by watching them we will be able to diagnose them as false.

And if I'm right, then videotaped interrogations may pose a particular danger precisely because of their power. I think we’re likely still to see some false confessions, and we’re likely still to see some judges and juries persuaded by these false confessions and believing in their truth.

BOB GARFIELD:  Jennifer, thank you so much.

JENNIFER MNOOKIN:  Thank you for having me.

BOB GARFIELD:  Jennifer Mnookin is a law professor at UCLA.