In that article the hacker claims he found sensitive material, and even flagrantly taunted the CIA director with it...
A ton of info. was posted on his twitter account that is now suspended. For DHS and FBI to investigate, they must have solid evidence of a breach to do so.
I don't see anything there that wouldn't be publicly available on the internet.
The one where you can buy pretty much anyone's (with a credit history) for $1.8?