This memo could be the smoking gun that investigators have been looking for.

这份备忘录可能是调查人员一直在寻找的证据。

《牛津词典》

The smoking gun. The evidence.

冒烟的枪，这就是证据！

youdao

The smoking gun was the lipstick on his shirt.

他衬衫上的口红就是铁证。

youdao

And here is the smoking gun sentence right here.

这是确凿的证据。

麻省理工公开课 - 固态化学导论课程节选

According to the Smoking Gun, Andrews was just one of 16 female reporters he targeted.

FORBES: The Erin Andrews peephole pervert gets 30 months, while millions of video-watching perverts go unpunished

Even so, experts have yet to find the smoking gun for the alleged theft of our neurons.

FORBES: Are Smartphones Making Us Dumber?

The Smoking Gun said it had been in contact with the hacker, who goes by the alias Guccifer.

BBC: Hacker exposes ex-US President George H W Bush emails