They may have been highly strung in the Wild West (5,7)

I believe the answer is:

horse thieves

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'they may have been highly strung' is the definition.
I don't know anything about this answer so I can't tell whether this works.

'the wild west' is the wordplay.
I cannot quite see how this works, but
an anagram of 'the' is 'eth' which is within the answer.
This explanation may well be incorrect...

'in' is the link.

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

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