Technology of gun detection

US experts are improving the technology to detect whether a person is carrying a gun in their mouth or not, in support of police work.

New York Police Department (NYPD) representative Raymond Kelly said he was impressed by the new technology that allowed police to detect a gunman at a distance.

On CBS 'Face the Nation, Kelly said the new technique uses terahertz technology.

"Basically, everyone emits terahertz radiation. And if that radiation is blocked by something, like a weapon, you can see its shape. We are currently testing. We received the newest prototype. And it's really promising, ' said Kelly.

The prototype device is too large to be deployed in the field, according to Kelly, compared to the case of a cell phone 20 years ago.

Mr Kelly said NYPD is discussing with lawyers the possibility of using new technology to avoid being targeted by people's advocacy groups over the privacy of their people.