DOJ could look into it. There are a lot of things that could and should be looked into..clinton at top of list
The only reason to look at Manafort and not Devine is because Manafort was briefly associated with the Trump campaign.
Both Manafort and Devine consulted for Yanukovytch. If they want to investigate Russia Russia Russia then investigate Devine. Otherwise - as if it wasn’t already obvious - the investigation is an only attempt to smear Trump.
Mueller is a sleazy bastard. He has hired nothing but Democrats, including Clinton’s attorney. He has coached Comey. It’s a farce.
The whole thing is predicated on lies. DNI, DHS, and FBI didn’t conduct their own investigation - they relied upon a report produced by a Democrat backed company. The baseless dirty dossier was paid for Democrats (and, I suspect, Jeb Bush).