17 across
Police
chief
overrides
law
for
possibly
harmful
agents
(8)
Police chief overrides law for possibly harmful agents (8)
hints
0
checks
0
hints
The definition is at the end of the clue.
How the clue works
You're after possibly harmful agents, meaning germs. The police chief is the notorious Soviet one, BERIA, and "overrides" tells you to drop ACT (a law) on top of him, which means slotting it inside after the first letter. So B, then ACT, then ERIA gives you the answer.