Tamerlan, 29, died in an exchange of gun fire with the police on April 18.
He is suspected to be the mastermind and the main suspect to the twin bombings in Boston that killed three people and injured more than 200 people early this month.
Police says Tamerlan had returned to the US from a six months trip to Russia during which he travelled to Chechnya and was radicalised. The trip could hold the key to the Boston bombing.
He was referring to the information provided by the Russian agencies on the Tsarnaev brothers two years before the terrorist attack.
Coats said the Russians have provided the US with some additional information.
"Now they've released some more information that may have the -- one thing we have to do, though, is make sure that we simultaneously send any of these pings that happened when the brother, the older brother came back, that didn't get sent to the whole network," he said.