The former chair said Trump needs to give Putin a copy of the indictment.
Vladimir Putin has repeatedly claimed it wasn't a Russian state effort.
The shooting caused large protests on Saturday night.
Some people complained of bleeding from their ears.
The Kremlin hopes it can restore normal communication channels with the U.S.
"I think we're greatly hampered by this whole witch hunt that's going on in the United States. The Russian witch hunt. The rigged situation," the president said
Nearly three dozen were sent to the hospital after the flight.
Both coasts will be dealing with 90-degree weather on Monday.
The 10 Democrats running in Trump-won states stretch across a wide swath of Democratic politics, and are all vying for their political survival in 2018 in distinct ways.
Police say the man was "exhibiting characteristics of an armed person".