Sleuth ultimately enthralled by footprints and fibres (7)

I believe the answer is:

threads

I'm a little stuck... Click here to teach me more about this clue!

'fibres' is the definition.
(I have seen 'Thin fibres ' mean 'threads' so perhaps 'fibres' could also mean 'threads')

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for threads that I've seen before include "Trashed (anag)" , "Strands of yarn" , "Hardest (anag.)" , "makes way so carefully" , "Lengths of yarn" .)

I've seen this clue in The Hindu.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.