The Rev Dodgson said:

Michael V said:

The Rev Dodgson 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.

Further discussion:

If I intend to lie, but I am mistaken, and tell you a true fact thinking it is false, am I still lying, or am I telling the truth?