Undercover agents are police who work undercover to investigate crime and are totally different from little security informants.

警察从事秘密的调查活动才叫卧底，完全不同于治安小信息员。

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Ford, who spent years undercover, has two golden rules to help agents keep from getting their cover blown.

福特做过几年的卧底，有两条铁律使他不至暴露。

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We put out an APB with the other FBI district offices and got lucky this morning when one of our own undercover agents saw him in South Central. We were ready to pounce...

汉斯莱流利地说，“我们向FBI的各地方分局发出了全境通告，今天早上我们的一位密探幸运地在中南区发现了他。”

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Among other things, such connections could be used to identify undercover agents, through link analysis.

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The Transportation Security Administration said a "small percentage" of the undercover agents - authorized to use deadly force to thwart terrorist incidents - had been placed on administrative leave.

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Although in this particular case, there was never any danger of the plot coming to fruition, since the only people that Ferdaus was working with were undercover FBI agents, it does beg the question as to whether such a plot could succeed in the first place.

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