Michael V said:

The Rev Dodgson said:

dv said:

It was Alex.

I will have to give it further ponderation to find something to be pedantic about.

By George, it was Georgie!

OK, it could have been George, or Fred, or perhaps no-one.

Then Alex is telling the truth,
Bob genuinely thinks it was Chris, but is wrong.
And Chris is wrong to say that Bob was lying, when he was just mistaken.