Three notes from criminal gang (5)
I believe the answer is:
triad
'criminal gang' is the definition.
(I've seen this before)
'three notes' is the wordplay.
'three' becomes 'tri' (prefix meaning 'three').
'notes' becomes 'ad' (two musical notes).
'tri'+'ad'='TRIAD'
'from' is the link.
(Other definitions for triad that I've seen before include "Chinese secret society" , "trio" , "Up to date" , "Union of three" , "Group or set of three" .)