"We Had To Come in Shooting. His Heart Rate Demanded It."

Given Radley Balko's many writings on the, er, excessive enthusiasm (OK, criminal recklessness) common among SWAT teams doing home invasions, I'm alarmed by this tidbit at the end of a BBC account of surveillance technologies:

So far there is no gadget that can actually see inside our houses, but even that's about to change.

Ian Kitajima flew to Washington from his laboratories in Hawaii to show me sense-through-the-wall technology.

"Each individual has a characteristic profile," explained Ian, holding a green rectangular box that looked like a TV remote control.

Using radio waves, you point it a wall and it tells you if anyone is on the other side. His company, Oceanit, is due to test it with the Hawaiian National Guard in Iraq next year, and it turns out that the human body gives off such sensitive radio signals, that it can even pick up breathing and heart rates.

"First, you can tell whether someone is dead or alive on the battlefield," said Ian.

"But it will also show whether someone inside a house is looking to harm you, because if they are, their heart rate will be raised. And 10 years from now, the technology will be much smarter. We'll scan a person with one of these things and tell what they're actually thinking."

Figuring out whether detected heart rates give a reasonable cop excuse for coming in shooting is one of those legal and strategic conundrums we'll be sweating over in the magically transparent world of tomorrow.

See Julian Sanchez's January cover story on many other such issues raised by surveillance and search technologies.