(PHILADELPHIA) -- Two 18-year-old men have been taken into custody in connection with a mass shooting at a SEPTA bus stop in Philadelphia last week, authorities announced Monday.
Charges against the two 18-year-olds include criminal attempted murder, aggravated assault and conspiracy, Philadelphia District Attorney Larry Krasner said.
At about 3 p.m. Wednesday, three masked gunmen exited a car parked near the bus stop and fired more than 30 rounds toward high schoolers who were trying to board a bus, Philadelphia police said.
Eight teens -- ages 15 to 17 -- were shot, and two of them were hospitalized in critical condition, police said. One of the teens was shot nine times, according to police. That victim has since been "upgraded [at the hospital] and is talking," police said Monday.
Philadelphia Police Commissioner Kevin Bethel called it a "heinous crime."
A fourth suspect remained in the car during the shooting, police said.
Bethel said one officer's tourniquet application may have saved a victim’s life.
While two of the four suspects believed to be at the scene are in custody, two remain at large, police said Monday.
"We're not done," Philadelphia Police Deputy Commissioner Frank Vanore said during a news conference. "We have other people that we need to contact. We know who they are and we're gonna continually move with our investigation."
"If you are in any way a witness to what occurred here, please reach out to the Philadelphia Police Department immediately," Krasner said. "If you are involved, then get smart -- turn yourself in."
Police said they recovered a gun that matches multiple casings from the shooting scene: a fully loaded .40 caliber Glock 22 pistol with an extended magazine.
"It also had laser sights on it. And it had what we call a Glock switch, which made that firearm fully automatic -- it was a machine gun," Vanore said.
Mayor Cherelle Parker addressed Philadelphia residents at the news conference, saying, "I've heard you tell me that you are afraid and concerned about riding SEPTA. You have told me that you have concerns about going to work, to school, to the store."
"To the people of our city: We want you to know that we are unapologetic about engaging every partner available to assist us," she said. "Every partner who is needed to assist our Philadelphia Police Department and work in partnership with them to get answers and to assure that folks are held accountable for their actions, they will work together to get it done."
All eight victims attend Philadelphia's Northeast High School, according to Philadelphia ABC station WPVI.
The mayor said, "We just left a meeting a few minutes ago with the principal of Northeast High School and he said to me that, 'Although our city and those children's lives were shattered last week, we will not be broken.' And we won't."
The mass shooting was just the latest in an outbreak of gun violence in Philadelphia, and the fourth shooting involving a local SEPTA bus in one week, according to WPVI.