“This was a terrible tragic situation, and this traumatized the community. We are begging Congress to protect lives and do something about America’s gun problem,” Philadelphia Mayor Jim Kenney (D) said Tuesday.

Police are still searching for a motive into why the 40-year-old male shooter, who police have not publicly named, opened fire shortly before 8:30 p.m. The man was shooting “aimlessly at occupied vehicles and individuals on the street as they walked,” Philadelphia Police Staff Inspector Ernest Ransom said.

At this point, there is no known connection between the shooter and any of the victims, according to authorities.

When the suspect was cornered and surrendered, police found “multiple magazines” of ammunition on his bulletproof vest, a nine-millimeter handgun as well as a police scanner, they said. Charges had not been filed against the unnamed suspect late Tuesday afternoon, but an arraignment is scheduled for Wednesday.

“Once the suspect has been formally charged and arraigned, we will release the suspect name along with the mug shot. That could be sometime tomorrow,” said Miguel Torres, a spokesperson for the Philadelphia Police Department, in an email.

The five who were killed are all male, Philadelphia Police Commissioner Danielle Outlaw said. Police identified them on Tuesday afternoon as Daujan Brown, 15; Lashyd Merritt, 20; Dymir Stanton, 29; Joseph Wamah Jr., 31; and Ralph Moralis, 59. Brown’s address was unknown; the other victims all lived close to the scene of the shooting. Two children who were shot, ages 2 and 13, are in stable condition, Outlaw said. Two people were also injured by broken glass during the shooting, according to police.

Four victims were pronounced dead at Presbyterian Medical Center after arriving, police said during a news conference Tuesday. Several hours after the shooting, police found a fifth person dead in his living room, with investigators confirming that the death was linked to the mass killing, Ransom added.

Police initially identified a second suspect who they said was taken into custody after the person picked up a gun and fired toward the shooter. Larry Krasner, Philadelphia’s criminal justice reform-minded district attorney, said Tuesday that the second person, who was also not named, has been released.

“We do not see a basis for concluding that that person’s discharge of a firearm was illegal,” Krasner said. “When you’re under fire in a mass shooting, there are rights to protect others and to protect yourself. Obviously, the investigation is not complete, but we are not in the practice of holding people in custody when we do not have probable cause.”

The shooting in Philadelphia is the fifth mass killing this year that involved an AR-15-style firearm, according to a Washington Post analysis, and is the latest incident to highlight the scourge of mass shootings in the United States. Tuesday marks the first anniversary of the deadly shooting at a Fourth of July parade in Highland Park, Ill. Highland Park suspect Robert Crimo Jr. is accused of using an AR-15-style rifle to kill seven people and injure dozens more.

Outlaw, who on Tuesday called the shooting in Philadelphia “unimaginably disgusting, and horrifying,” joined other public officials in characterizing gun violence as a persistent problem for the city.

During the news conference, Krasner called out legislators in Congress who have voted against gun-control legislation, and taken to wearing AR-15 lapel pins, like the ones Rep. Andrew S. Clyde (Ga.) handed out to fellow GOP lawmakers this year.

“A lot of us have had enough of that. I can tell you I certainly have had enough of it,” Krasner said. “It is time for everybody in our legislature, including the ones who would like to walk around with an AR-15 lapel pin, it is time for every one of them to face the voters.”

As of Sunday, Philadelphia had registered 212 homicides so far in 2023, a 19 percent decrease from the same period last year, according to data from the municipal government.

Philadelphia City Council member Jamie R. Gauthier (D), who represents areas where the shooting occurred, described her district as “under siege” by gun violence.

“It creates a situation where mostly Black and Brown people can’t be in their neighborhood enjoying summer weather. Kids – anyone – enjoying their block should not live in fear of being shot and killed,” she said Tuesday.

Now that Democrats control the state House for the first time in 12 years after November’s election, Gauthier said some movement on gun-control legislation has started. However, any House bills would still face opposition in the GOP-controlled state Senate.

“In Pennsylvania, you have Philadelphia and Pittsburgh in the cities, and outside of that, you have a lot of rural areas that don’t look like us and don’t have the same issues with everyday gun violence – and don’t have the same motivation to really cut off access to these types of weapons,” Gauthier said. “We have a long way to go to get these kinds of weapons off the street.”

Monday’s mass killing appears to have been the country’s 28th with a gun this year – a trend that Kris Brown, president of the Brady Center to Prevent Gun Violence, called “a uniquely American crisis.”

“Gun violence shouldn’t be as American as the 4th of July. But the tragic reality is the July 4th weekend is often our country’s deadliest peak in gun violence,” Brown said in a statement. “Already, 2023 is on track to set the record for the highest number of mass shootings of any year in U.S. history.”

President Biden invoked the Philadelphia shooting and last year’s mass killing in Highland Park in a statement Tuesday that called on congressional Republicans to “come to the table on meaningful, commonsense reforms that the American people support.”

Biden, who supports a federal ban on assault weapons and high-capacity magazines, has struggled to enact his vision in a divided Congress where many Republicans balk at restricting gun access. The president has praised state and local leaders such as Illinois Gov. J.B. Pritzker (D) and Highland Park Mayor Nancy Rotering (D) for working together to pass state-level bans.

“Today, Jill and I grieve for those who have lost their lives and, as our nation celebrates Independence Day, we pray for the day when our communities will be free from gun violence,” Biden wrote.