WILLINGTON, Conn.  - Cargo theft has become a huge problem that the FBI says causes $15 billion to $30 billion in losses each year in the U.S.
    
Law enforcement and the insurance industry are fighting back by tempting thieves with "sting trailers" laden with cameras and GPS tracking devices, hidden within both the trailers and the inventory they contain.
    
The prevention efforts aren't new. But the reason for them is particularly acute during the holiday shopping season, when such thefts tend to increase as crooks look to score from retailers loading up on merchandise.
    
Over time, the sting trailers have given authorities a glimpse into how this breed of thief operates and helped truck owners improve security.