re: Seek Thermal. Thermal imaginging device that hooks up to cell phone

Wouldn't have to be cold, my FLIR camera can pick up the warmer paw prints my cat leaves on carpet easily. Blood would show up as a cool spot on warm ground as the water content evaporates too. That's why these cameras can show even the slightest damp spot from a leak. On drywall, a leak behind the ceiling or wall could be detected even if the surface you can see is dry to the touch.