The ancient Greek world had no single system of law; individual states instead formed their own political and legal systems, although these were arguably based largely on the same general principles.
The most widely-known Greek judicial system is that of 4th century classical
Possible starting points are:
Commentary on Bodleian Law Library shelves
The section with shelfmarks Ancient Greek can be found on Level 2. Below are some examples.
NB. If this is your area of research you will undoubtedly need to consult works in the Bodleian Sackler Library too.See the box in the right hand box for some examples.
Plato's various records of the trial & execution of his teacher (The Euthyphro, Apology of Socrates, Crito, part of the Phaedo)