Punches were thrown and property damage inside the diner, on Aramingo Avenue near Ontario Street, ranged from broken gumball machines to broken tables, police said. About 50 patrons were inside at the time, according to police.
"It was crazy, it was a mess," the detective said.
At one point, a 21-year-old man pulled out a gun and shot a 28-year-old man from the opposing group once in the head, police said.
The shooter, whose name was not released, ran off but was apprehended at his mother's house, police said. He was expected to be charged with attempted murder and related offenses. Police said that he had 20 prior arrests.
The victim, who is from out of town, was listed in critical condition yesterday at Hahnemann University Hospital. His identity was not released.
The weekend's violence started about 9 p.m. Friday, when Julio Augustine, 21, was fatally shot on the block where he lived, Rutledge Street near Cambria, in Kensington. Shot multiple times in the torso, he was pronounced dead at the scene.
Shortly after that, at 10:20 p.m., a musician with the Dunamis Temple Church, on Germantown Avenue near 9th Street, in North Philadelphia, was outside the church when he argued with a passer-by, police said.
Either that passer-by or a man who was with him pulled out a black semi-automatic handgun and shot the 23-year-old musician in the arm, back and chest, according to police.
Two of the musician's fellow congregants, who were licensed to carry firearms, came to the victim's aid, returning fire at his attackers, police said.
It's unknown whether either of the men, who fled on foot, was hit.
The victim, who was taken to Temple University Hospital, remained there yesterday in critical condition.
Less than two hours later, shortly after midnight Saturday, police were called to 61st and Ludlow streets, in West Philadelphia, for a report of an auto accident.
Investigators found that the car in question - a black-and-white taxi - had crashed into a pole and that the driver had been shot once in the back of the head, according to police.
The driver, Aliou Diallo, 50, of Lindbergh Boulevard near Buist Avenue, was taken to the Hospital of the University of Pennsylvania, where he was pronounced dead at 3:38 p.m.
It's not certain whether robbery was a motive for the shooting, because cash was found at the scene, police said.
Investigators also were seeking a motive in the death of Darryl Walton, 16, who was found at 11:17 p.m. Saturday on Euclid Street near Georges Lane, in Wynnefield, with a bullet wound to his upper left back.
Walton, of Montgomery Avenue near 52nd Street, was pronounced dead at the scene by medics at 11:29 p.m.
His killer remained at large yesterday.