Clue: X, mark probing new evidence of collision — get the law! (3,12)
Answer: TEN COMMANDMENTS
Explanation: Definition: the law
**TEN** ("X") +** COMMA** (,) + **M** (mark) *probing* **N** (new) **DENTS** ("evidence of collision"), so **TEN-COMMA-N-D(M)ENTS