Sentence:  ‘I had my researchers check the files on all the mispers and <WSD>cold cases</WSD> five years either side of that date estimate, on females of that approximate age. This is what they found. Fill your boots.' He took a large gulp of his drink. / ‘I'm impressed, you've been moving fast.' / ‘On it like a car bonnet, mate.' 
Meaning of the word marked with <WSD> tags:  A criminal investigation that has not been solved after a considerable time but remains “on the books” and may be reopened when new evidence appears.