He messaged Omniscient / "the admin" on a HackForums / another HF clone site, asking about a PII dump with his own personal Gmail being specified, inquiring about GREP help.
When the entire DB leaked, his personal message was the most obvious one.
You all think these people are cyber geniuses, but really, just sufficiently advanced scum bags in socioeconomically-disadvantaged, politically convenient areas to operate these neo-scams.