3 Dead, 11 Wounded in Philadelphia Shooting on South Street

As the weekend’s violence unfolded, senators in Washington continued working to strike a compromise on legislation that would expand the nation’s background check system as well as allocate money for mental health resources, school security and the implementation of “red flag” laws across the states.

Two veterans of failed negotiations in the past — Senator Christopher S. Murphy of Connecticut, a Democrat, and Patrick J. Toomey of Pennsylvania, a Republican — said in separate interviews on Sunday that they believed they were closer to a deal than compared with previous attempts.

“It’s a test of the federal government as to whether we will deliver at a moment of just fierce anxiety among the American public, so we’re closer than ever before,” Mr. Murphy said on CNN’s “State of the Union.”

Mr. Murphy acknowledged that an assault weapons ban and a universal background check law will not be part of a final compromise in order to win the necessary Republican votes, even as House Democrats prepare to force a series of votes on individual gun bills that do not have Republican support.

Mr. Toomey, who saw his own party filibuster the background check deal he helped strike with Democrats after the Sandy Hook shooting in Newtown, Conn., in 2012, said he hoped to see at least half the Republican conference in the Senate support a final agreement.

Back in Philadelphia, Mr. Chen, the cashier, was simply preparing to return to business as usual. Although the attack there had made him nervous, he was not entirely surprised by it, given other recent shootings across the United States.

“It happens all the time,” Mr. Chen said. “You just go on with your day.”

Reporting was contributed by Stacy M. Brown, Cari Wade Gervin, Vimal Patel, Tiffany May ,Christopher Mele, Emily Cochrane, Mitch Smith and Dakota Santiago. Kitty Bennett contributed research.