Four people were killed and two were injured in a shooting on Monday night in Philadelphia, and a suspect was taken into custody, Philadelphia Police Commissioner Danielle Outlaw said at a late night news conference.

The suspect, a man believed to be 40-years-old, did not appear to have any connection to the victims, Outlaw said, adding that he had a bullet-proof vest and a police scanner.

A second person was also taken into custody in connection with the shooting, she said. It was unknown whether this person was connected with the shooter, but police believe he returned fire at the shooter, Reuters reported.

There were three guns recovered from the scene, including a rifle and a handgun that belonged to the suspect, she said at the conference.

The ages of the three dead, all males, ranged between 20- and 59-years-old. The fourth male was believed to be between the ages of 16 to 21. The two injured children are two- and 13-years-old. They were in stable condition, Outlaw said.

Details of the July Fourth-eve gun violence were sketchy, but the shooting was reported to have erupted in the Kingsessing section of southwest Philadelphia, less than two kilometers from the Schuykill River that flows through Pennsylvania’s most populous city.

WPVI video footage from the scene of the shooting showed several police squad cars parked near an intersection, lights flashing in the darkness, with portions of the street cordoned off with yellow and red crime-scene tape.

The shooting came a day after two people were shot dead and 28 others injured, about half of them children, in a hail of gunfire at an outdoor neighborhood block party in Baltimore, Maryland. Police said they were still seeking multiple suspects in that shooting.