A Trump lie's non-malignant? It's a killer (6,7)

I believe the answer is:

donald neilson

'a killer' is the definition.
(British serial killer)

'a trump lie's non-malignant?' is the wordplay.
'a trump' becomes 'donald' (Donald Trump).
'malignant?' indicates an anagram (I've seen 'malignant' mean this).
'lies'+'non'='liesnon'
'liesnon' is an anagram of 'neilson'.
'donald'+'neilson'='DONALD NEILSON'

'it's' acts as a link.

I've seen this clue in The Guardian.

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