There's been another blow to prosecutors in the Robert Kraft case. Last year, the New England Patriots owner was arrested for allegedly paying for sex at a massage parlor in Florida. Now, an appeals court there has ruled that video footage from surveillance cameras set up by police cannot be used by prosecutors. Northeastern Law Professor and WGBH News legal analyst Daniel Medwed discussed the case with All Things Considered host Arun Rath. The transcript below has been edited for clarity.

Arun Rath: Let's start with the central issue here, the video evidence in this case. Give us the legal outline. When is it OK for law enforcement to use recording gear to document a crime and what was not OK, at least according to this ruling, about what happened in the Kraft case?

Daniel Medwed: One of the big issues in the 21st century with law enforcement, of course, is the extent to which the authorities can use electronic surveillance techniques to gather information against criminal suspects. For the most part, you have to obtain a warrant. You have to have probable cause of criminal activity, and the warrant has to specify with particularity what you're looking for. There have to be what are called "minimization restraints" that restrict your use of the technology to make sure that innocent people aren't swept under its brush.

So what happened here is that police used a warrant to get some hidden cameras in the massage parlor, but they didn't have sufficient minimization requirements to protect innocent people. And that was really the problem.

Rath: So would it have made a difference, say, if they were going specifically after just Robert Kraft? The issue was they cast a wide net?

Medwed: I think that's right. So the idea is, they knew about lots of illegal prostitution activities happening at this particular massage parlor because they had seen people coming and going at odd times, staying for odd durations. They also had heard rumors in the community about this activity. So they had a sufficient basis to get the warrant and to get the cameras. And if they had known about Robert Kraft and they had set it up in a room where they suspected he'd go, there probably wouldn't be a problem.

But they did, as you suggest, have a very wide net. It was a five day warrant, 24 hours a day, for five days. The Jupiter, Fla., police could monitor what was happening in, I believe, four different rooms in the massage parlor, as well as in the lobby.

And what happened is, yes, a lot of the people who went to get massages did pay for sexual services. They, in fact, engaged in criminal activity. But a number of people went there just for regular massages, and they were also captured on these hidden cameras in various stages of being disrobed. That implicated some very serious privacy interests, which in turn tied into some very important Fourth Amendment privacy interests.

Rath: This throws out this very important evidence, but it doesn't throw out the case. Are there other routes for prosecutors to take now in pursuing Kraft?

Medwed: They could. So you could pursue him without the video evidence, but it's going to be a challenge, in part because this massage parlor seemed to have both legal and illicit activities happening. As I mentioned, there were some people just getting regular massages. So it would be very, very hard to prove that the reason Kraft went there was to do something illicit. It was the video evidence that was damning and damaging to him, and without it, I really don't see a way forward. They could plow forward. They could also appeal this decision to a higher court, in Florida, the Florida Supreme Court. But I think the likely outcome is that they may drop the charges.

Rath: For some context on this, Daniel, is this a case where maybe this sort of thing happens all the time and just because this was a case where we have Robert Kraft with his lawyers, that it was thrown out in a situation like this?

Medwed: The courts are very vigilant about electronic surveillance techniques. In fact, just about 10 days ago, our Supreme Judicial Court in Massachusetts ruled that the use of hidden cameras that were affixed to telephone poles to target suspects were really problematic. That wasn't a very high profile case, it was out in Essex County. I think the idea is that courts are really concerned about privacy in this new electronic world. So, yes, the fact that Bob Kraft was involved, that's the reason we all know about it, but I suspect the result would have been exactly the same.

Rath: How do these vary by state? If this were, say, not in Florida, if it were in Massachusetts or some other state, could this have turned out differently?

Medwed: It could. It does vary considerably from state to state, and this panel, the 4th District for the Court of Appeal in Florida, relied specifically on Florida case law to hold that the absence of these minimization requirements that I mentioned that would limit how the authorities viewed or use these cameras - that that was really the problem.

In Massachusetts or other states, it could have turned out differently, but I suspect at least in Massachusetts, the courts would have also had problems with this type of wide net.