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。

The search for other kinds of evidence tying him to trafficking has not produced a smoking gun.

在其它方面还没有找到能证明他参与此非法交易的确凿证据。

The smoking gun. The evidence.

冒烟的枪，这就是证据！

The smoking gun was the lipstick on his shirt.

他衬衫上的口红就是铁证。

The smoking gun was the lipstick on his collar .

他衣领上的口红是确凿的证据。