 CBS News legal contributor Rebecca Roife. The holiday week last week proved deadly across the country, all due to gun violence. CBS News correspondent Matt Piper with those numbers. During the July 4th holiday week, 340 people were killed and another 756 injured across the U.S. That, according to the Gun Violence Archive, which says there were 20 mass shootings between July 1st through 7th. The worst in Chicago, Police Superintendent Larry Snelling.