'I'd stab criminal', admits gangster in dock (5,5)

I believe the answer is:

tidal basin

'dock' is the definition.
(tidal basin is a type of dock)

'i'd stab criminal admits gangster in' is the wordplay.
'criminal' indicates anagramming the letters.
'admits' indicates putting letters inside.
'gangster' becomes 'al' (Al Capone).
'id'+'stab'='idstab'
'idstab' with letters rearranged gives 'tidbas'.
'tidbas' enclosing 'al' is 'tidalbas'.
'tidalbas'+'in'='TIDAL BASIN'

I've seen this clue in The Guardian.

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