The phrase 'case law' refers to one of the ways in which law is made. Case law is created when the courts decide a case, which then becomes a precedent for similar cases that arise in the future.
A 'law report' is the written account of a decided case. It is in the law reports that one finds the facts of the decided case, and the law that was applied to decide that case. Law reports are collected together and published in various 'law reports series'.