Keeps the peace at lake in Italy (5)

I believe the answer is:

garda

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'lake in italy' is the definition.
(I've seen this in another clue)

I don't understand how the rest of the clue works.

(Other definitions for garda that I've seen before include "An Irish limb of the law" , "Policeman of the Irish Republic" , "Italian lake - Irish policeman" , "Irish state police force" , "Irish police officer" .)

I've seen this clue in The Irish Times.

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