2 in custody in connection to Philadelphia's South Street shooting

• A second suspect, who wasn't identified Monday, was taken into custody by the U.S. Marshals Service later in the day, District Attorney Larry Krasner told CNN.

Catch up quick: Police believe that one of the three individuals killed in the mass shooting on South Street's popular business corridor of bars and restaurants was a suspected shooter involved in an altercation leading up to the tragedy.

• Police are investigating "several" other shootings in the area Saturday, but it remains unclear whether they're connected.
• Krasner said Monday that at least four guns — three 9 mm weapons and one 40-caliber gun — were involved in the shooting.

What's next: An investigation is still ongoing. No murder charges have been filed at this time, the District Attorney's Office said.

• Police are looking to identify additional people involved.

Editor's note: This is a developing story. Check back for details.