线索

Please give me some track to it.

There is a clue for solving this.

The clue could not be followed up.

clues for solving a case

thread of a story

follow up a clue

keep track of

look for clues

provide/offer/give/supply a clue

lose track of

leave a clue

gain/find a clue

discover a clue

trace a clue

divulge a clue