Line in US pursued by some police hero (2,3)
I believe the answer is:
Here is my best explanation:
'hero' is the definition.
(I've seen this before)
'line in us pursued by some police' is the wordplay.
'line in us' becomes 'el' (short for elevated railway line in the US).
'pursued by' is a charade indicator (letters next to each other).
'some police' becomes 'cid'.