UPDATE (Friday, October 13th 6:47pm ET): Stone's attorney tells CNN the following:
"Mr. Stone has complied with the committee's requests. No further statement will be issued."
Representatives Adam Schiff (D-CA) and Mike Conaway (R-TX) tell CNN they are prepared to subpoena Roger Stone if he doesn't reveal by Friday who served as his intermediary to Wikileaks' Julian Assange.
When Stone testified before the House Intelligence Committee behind closed doors on September 26th, he refused to reveal his connection, claiming the person was a journalist and the conversations were off the record. Rep. Schiff warned at the time that his committee would subpoena Stone if he failed to volunteer the information.
Roger Stone faces subpoena threat over Assange contact (CNN)