Once again, HP smartly deduced that ...

e.g.

cleverly put two and two together
cleverly connect the dots

fallen mir ein als Möglichkeiten

Smartly doesn't quite fit, imo.
Cleverly put two and two together is perfect, I'd say.

Or

Hercule Poirot has once again cleverly joined up the dots.

Ginge auch Folgendes (als Kombination der obigen Vorschläge):

Once again, HP has cleverly put the facts together and deduced that...

I don't know why "smartly" wouldn't fit (as per Mini Cooper). It works fine in AE.

Edit: your version is fine, Kahtze.

@ 5: FWIW, ich finde diese Deine Version korrekt, Kathze.