Sen. Richard Blumenthal's aide passed him a note alerting him of the deadly shooting unfolding at Saugus High School in Santa Clarita, California.
The 16-year-old gunman, a student at the school, died Friday after shooting himself in the head, according to officials.
An attorney for five survivors says festival organizers failed to secure the event's perimeters and to protect people from "the foreseeable risks of mass shootings."
The demonstration is part of a last-ditch effort to have Rodney Reed's case reevaluated in light of new evidence before his execution, scheduled for Nov. 20.
The public "like" counter may disappear as early as next week for some U.S. Instagram users. The app rolled out the test in other countries earlier this year.
A bipartisan group of Texas senators and representatives issued two separate but identical letters as support for the death row inmate's commutation grows.