Crossword Genius

One who questioned engineers in Rio quits (10)

Ross

I believe the answer is:

inquisitor

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'one who questioned' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.

'engineers in rio quits' is the wordplay.
'engineers' indicates anagramming the letters (I've seen 'engineer' mean this).
'in'+'rio'+'quits'='inrioquits'
'inrioquits' is an anagram of 'INQUISITOR'.

Can you help me to learn more?

(Other definitions for inquisitor that I've seen before include "Searching questioner" , "Investigator, examiner" , "One questions" , "Exacting investigator" , "Torquemada, for example" .)

I've seen this clue in the Sydney Morning Herald.
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