Crossword Genius

Leaders go to the bottom with crime detector (5)

Ross

I believe the answer is:

sonar

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'detector' is the definition.
(I have seen 'Underwater detector ' mean 'sonar' so perhaps 'detector' could also mean 'sonar')

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for sonar that I've seen before include "Locating device" , "Underwater detection device" , "Device for detecting objects under water with sound waves" , "Echo-sounding device" , "Underwater detector" .)

I've seen this clue in The Hindu.
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