The experience which Liz had was a most unpleasant affair and it's no wonder that she was frightened. It happened while she was living abroad and that made it even worse, because it is always hard to understand the operation of the law in a foreign country.
Liz mentions the C.I.D. which is the Criminal Investigation Department of the police force in England. Of course, the equivalent in another country would not be called the C.I.D., but for an English person it is quite usual to say C.I.D., meaning the special department which deals with crime.