What does "I've got your number" mean? Is it an idiom?

[Zishuli]

English Language Tests, Intermediate level

ESL/EFL Test #379 "English Slang Idioms (100)", question 3

"That's alright. You can lie to me if you want to right now, but I've got your .......... Now that I know what you are doing, I just have to figure out how you are doing it and then I am calling the police," the boss told Jeremy.

(a) address
(b) motive
(c) nature
(d) number

English Language Tests, Intermediate level

ESL/EFL Test #379 "English Slang Idioms (100)", answer 3

"That's alright. You can lie to me if you want to right now, but I've got your number. Now that I know what you are doing, I just have to figure out how you are doing it and then I am calling the police," the boss told Jeremy.

Correct answer: (d) number

Your answer was: correct
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Hi,

" I've got your number"---what does it mean ? Can anybody help me ?

[Mister Micawber]

.
'I understand you' (especially, 'I understand your tricks/deceits').
.
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Native English teacher at Mister Micawber's