Located the cause of the trouble and was critical (5,5)

I believe the answer is:

found fault

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'the trouble and was critical' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'located the cause' is the wordplay.
'located' becomes 'found' (I've seen this in another clue).
'the cause' becomes 'fault' (I can't explain this - if you can you should believe this answer much more).
'found'+'fault'='FOUND FAULT'

'of' acts as a link.

Can you help me to learn more?

I've seen this clue in The Globe and Mail.

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