Two teens accused of fatally shooting bystanders during Saturday’s mass shooting on South Street were arrested Thursday by U.S. Marshals in Virginia and were expected to face murder charges after being extradited back to Philadelphia, officials said.

The apprehension of Qaadir Dukes-Hill, 18, and Nahjee Whittington, 17, marked the end of a five-day manhunt for five suspected gunmen in the shooting — a chaotic episode that spanned more than a block and left three people dead and 11 wounded. Those slain included one of the gunmen. Two of the wounded were also among those who fired shots.

“All the people responsible for the violence at this point are in custody,” Deputy Commissioner Ben Naish said at a City Hall news conference alongside officials including Mayor Jim Kenney.

The teens captured in Richmond, Va., who are friends, fired randomly into the frightened crowd packing South Street even though they had no ties to the other men who fired gunshots before them, officials said.

Police had arrested one suspected shooter Monday and charged another man with participating in a brawl that sparked the gunfire. A third gunman was killed in the incident, police said, while a fourth was critically wounded but won’t face charges because prosecutors determined he had acted in self-defense.

» READ MORE: How the South Street shooting unfolded, minute by minute

Dukes-Hill and Whittington, wearing matching hoodies, escalated the mayhem by pulling out handguns and firing moments after a gun battle had erupted on the 200 block of South Street — at least half a block from where the teens were standing, officials said.

“It appears they had guns and they took them out and randomly fired them,” said Joanne Pescatore, homicide chief in the District Attorney’s Office.

One of Dukes-Hill’s shots fatally struck 24-year-old Alexis Quinn, a home health aide, prosecutors said, while Whittington is accused of fatally shooting Kristopher Minners, a residential adviser at Girard College who was out celebrating his 22nd birthday.

Whittington is also expected to be charged with shooting another man in the calf, officials said, and both he and Dukes-Hill could face additional charges if ballistics tests reveal that their bullets struck other victims who survived.

“I’m very grateful that these men are off the streets, and I hope their capture brings a small bit of peace to the families and surviving victims,” Kenney said.

The teens were captured as City Councilmember Kenyatta Johnson held a roundtable discussion on gun violence in the wake of the tragedy, which also came after mass shootings in Buffalo, N.Y., and Uvalde, Texas. Police Commissioner Danielle Outlaw attended and was greeted with applause. She and other officials discussed attempts to balance long-term solutions with tackling the city’s current and sustained shootings crisis.

Elsewhere in Center City on Thursday afternoon, a group of about 100 faith leaders and supporters marched from the Cathedral Basilica of SS. Peter and Paul to City Hall, holding T-shirts bearing the names and ages of some of the more than 500 people killed by guns in Philadelphia last year — the highest annual total on record.

Minners’ parents, reached after officials revealed news of the teens’ arrests, said they were too distraught to comment, and were finalizing funeral arrangements for their son.

Attempts to reach Quinn’s relatives were unsuccessful. Family and friends had gathered Wednesday evening in Southwest Philadelphia to mourn and celebrate the 24-year-old — releasing black, purple, and white balloons into the sky.

Authorities have said the incident that led to the deaths of Quinn and Minners began as a confrontation between two groups of men around 11:30 p.m. Saturday on the 200 block of South Street.

That encounter started as a fistfight, court documents say, with Rashaan Vereen, 34, punching Micah Towns, 23, as the two men passed each other on the street. Prosecutors said it wasn’t clear if the men knew each other, and police didn’t know why Vereen threw a punch. But moments later, video shows Vereen and a friend — 34-year-old Gregory Jackson, a former professional boxer and youth coach — walking back toward Towns, and Jackson drawing a handgun.

As Jackson and Vereen began beating Towns, prosecutors said, Jackson fired his gun, striking Towns in the body and leaving him critically wounded. In all, the two men exchanged 17 shots.

Towns, lying in the street, was able to shoot back, killing Jackson.

Vereen then tried to tend to Jackson’s wounds, prosecutors said, and he gave Jackson’s gun to someone else passing by.

Meanwhile, moments later and across the street, 18-year-old Quran Garner — an apparent friend of Towns’ — began firing shots from a homemade “ghost” gun into the panicked crowd, prosecutors said. A police officer who arrived noticed Garner shooting and returned fire, striking Garner in the hand and causing him to run away, prosecutors said.

» READ MORE: South Street shooting victim Alexis Quinn remembered as a loyal, loving daughter who ‘brought people together’

As panic swelled and shots echoed through the busy nightlife corridor, police said, Dukes-Hill and Whittington — who were standing in different spots on the 300 block of South Street — pulled their guns and began firing.

Police did not say how many shots the teens rattled off. But Naish said video showed them “wantonly firing their weapons toward where the gunfire was originally happening.”

Neither teen was eligible to have purchased a handgun in Pennsylvania. But investigators believe Dukes-Hill fired a .40-caliber firearm that killed Quinn at the intersection of Third and South Streets, while Whittington shot a 9mm handgun, killing Minners and injuring at least one other person.

At least nine other bystanders were wounded by gunfire, police said, many of whom were hospitalized in stable condition.

Authorities earlier this week arrested Garner — the teen who allegedly fired the ghost gun — and Vereen, who is accused of starting the brawl with Towns. Vereen is charged with crimes including attempted murder, while Garner faces counts including aggravated assault.

Prosecutors said Towns had fired his gun in self-defense and would not face charges.

Then, later in the week, police released videos from the scene in an attempt to identify Dukes-Hill and Whittington. A flood of tips poured in, authorities said, and prosecutors approved warrants for their arrests. Investigators received information Wednesday that the pair might be in Richmond, and U.S. Marshals began surveilling the area.

Robert Clark, supervisor deputy of the U.S. Marshal Eastern District of Pennsylvania, said the agency already had a warrant out for Dukes-Hill’s arrest over his failure to appear in court for previous car-theft charges in Delaware County. Whittington, meanwhile, had previously been arrested for receiving stolen property, Clark said.

Marshals confirmed the pair’s location at an apartment complex Thursday morning, Clark said, and they were taken into custody around 12:15 p.m.

It was not immediately clear how quickly they might be extradited back to Philadelphia. They are expected to be jailed and formally arraigned on counts including murder upon their return.

Staff writers Sean Collins Walsh, Oona Goodin-Smith, and Vinny Vella contributed to this article.