Top ages in the secret police (7)

I believe the answer is:

gestapo

I'm a little stuck... Click here to teach me more about this clue!

'the secret police' is the definition.
(Nazi secret police)

'top ages' is the wordplay.
'top ages' can be anagrammed to 'GESTAPO'.
Though, I'm unsure how this is indicated.

'in' is the link.

Can you help me to learn more?

(Other definitions for gestapo that I've seen before include "Geheime Staatspolizei" , "Notorious secret police" , "Hitler's secret police" , "Men in black" , "State police in Nazi Germany" .)

I've seen this clue in The Irish Independent.

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