Trump tweeted on Monday morning.

I love riddles, Colbert taunted.

I know this one!

But why are you bringing it up, if youre not gonna do it?

Thats like a surgeon saying, Its just a routine appendectomy.

Also, I could kill you at anytime, but why would I do that?

Okay, no count backwards from 10.'

Trumps tweet came in response toaNew York Timesreportabout a 20-page letter to Mueller.

Nothing says innocent like Trump trying to convince Mueller that he can pardon himself, Colbert joked.

In no case can he be subpoenaed or indicted, he said.

I dont know how you could indict while hes in office.

No matter what it is.

He later added, If he shot James Comey, hed be impeached the next day.

Impeach him, and then it’s possible for you to do whatever you want to do to him.

So there it is: the president can commit any crime he wants, Colbert said.

Hes a one-man purge, which will make a great new campaign slogan.

Trump 2020: I could kill you in your sleep.'