Pick up leads for ecstasy criminals trafficked on county lines (7)
I believe the answer is:
collect
'pick up' is the definition.
(I know that pick up can be written as collect)
'leads for ecstasy criminals trafficked on county lines' is the wordplay.
'leads for' indicates taking the first letters.
'on' means one lot of letters go next to another.
'county' becomes 'co'.
'lines' becomes 'll' (an abbreviation for line written twice).
The initial letters of 'ecstasy criminals trafficked' is 'ect'.
'co'+'ll'='coll'
'ect' put after 'coll' is 'COLLECT'.
(Other definitions for collect that I've seen before include "Gather; pick up" , "mass" , "Assemble or bring together" , "Gather together, for a short prayer perhaps" , "Assemble - a short prayer" .)