I do not know if you are talking about the same person, but "bitcoinseller" (the nickname) is also on btc-e.

As soon as I spoke on their chat, he sent me a PM stating that he is willing to sell me bitcoins for $5.2, when the price on the website was $6.4.

I said just "hi" on the chat, nothing about buying bitcoins, so obviously he was contacting anyone that talked there.

I told him, ok, but to send the bitcoins first, he said he does not agree, and I asked him to search for another victim.

When something sounds too good to be true, it usually is.