Rioter's trial involved soldiers (12)

I believe the answer is:

territorials

'soldiers' is the definition.
(territorial is a kind of soldier)

'rioter's trial involved' is the wordplay.
'involved' is an anagram indicator (involved can mean confusing or complex).
'rioters'+'trial'='rioterstrial'
'rioterstrial' anagrammed gives 'TERRITORIALS'.

(Another definition for territorials that I've seen is " TA soldiers".)

I've seen this clue in The Independent.

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