Person carrying out investigation mistakenly pro-rapture (10)

I believe the answer is:

rapporteur

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'person carrying out investigation' is the definition.
I can't tell whether this definition defines the answer.

'mistakenly pro-rapture' is the wordplay.
'mistakenly' indicates anagramming the letters.
'pro'+'rapture'='prorapture'
'prorapture' anagrammed gives 'RAPPORTEUR'.

Can you help me to learn more?

(Other definitions for rapporteur that I've seen before include "researcher" , "One investigating" , "Recorder" , "Record-keeper" .)

I've seen this clue in The Irish Times.

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