fine-tooth comb

/F AY1 N T UW0 TH K OW0 M/
noun
  1. 1

    A comb with fine, closely-spaced teeth.

  2. 2

    A means of making a thorough search.

    โ€œThe police went through his possessions with a fine-tooth comb.โ€

verb
  1. 1

    To go over or through with a fine-tooth comb

  2. 2

    To search meticulously.

Source: https://en.wiktionary.org/wiki/fine-tooth%20comb