Submariners of the Gods (Doc Minus Two Book II)

What can sink a ship and disappear without a trace and is not a submarine? In the second novel in the Doc Minus Two series, this becomes a critical question when six fishing boats are mysteriously torpedoed in broad daylight, as if by an invisible predator. No one can determine who or what perpetrated the attacks, or where it came from. Both the U.S. and Mexican navies fail to find any signs that a submarine, a boat, a plane, or even a remote-controlled device was ever involved. The only hi...