The article quotes Rohrabacher like I did. You're right it does not say "tell us the Russians did this". It's Assange's lawyer who's filling that part in.
As well as other parts. No promise was made, and no specific answer was requested. That "lawyer" (assuming they even said what's being "reported") is working for the DNC, which is trying really hard to get ahead of some extremely damaging revelation (such as, for example, that someone at the DNC leaked the info, which would completely demolish what remains of the "Russian collusion" narrative they rode on for 3 years).
It makes zero sense otherwise for that lawyer to jeopardize Assange's "guaranteed" pardon.