Updated

Police are combing through surveillance video and have announced a reward they hope will lead to quick arrests of suspects in a quadruple shooting near a Catholic school in north Philadelphia where three men were killed and a fourth wounded.

Authorities said a group of men were standing on the block near St. Malachy Catholic School just after 3:30 p.m. Monday when they were approached by at least two people who fired numerous shots at them.

Tyair Jabbar, 20, was pronounced dead minutes later, and Ronald Fenwick, 32, was pronounced dead soon afterward at Temple University Hospital. Marcello Robertson, 27, died shortly before midnight at Hahnemann University Hospital. A 26-year-old man shot in the stomach was in stable condition, police said.

Homicide Capt. James Clark told reporters Tuesday that the shooting apparently happened "pretty quickly," noting that a gun was recovered from one of the victims who died at the hospital and he was unable to get it out in time to return fire.

"It appears they came down the street, and before these four knew what hit them, two of these individuals were firing shots at them," Clark said. All four victims have prior arrests, he said. Two suspects may have fled in a small gray sport utility vehicle, which was being sought, he said.

Clark said the area had a lot of surveillance cameras, and investigators plan to review hours of it to try to identify suspects. Investigators also have been examining social media but haven't found any threats that might have preceded the gunfire. Police plan to step up patrols to "flood the area" with police following the shooting.

"We're always worried about retaliation, we're always worried about them coming back and shooting or injuring more individuals in the area," he said.

Clark said a $60,000 reward, $20,000 for each victim who died, is being offered for information leading to suspects in the shooting, which happened near the school, which has students from kindergarten through eighth grade and was locked down as a precaution. The Philadelphia Housing Authority, which owns apartments near the scene, posted an additional $10,000, saying it was "firmly committed to the safety of our residents and the neighborhoods where our developments are located."

But nearly 24 hours after the shooting, police had received no tips as yet, even though more than 20 shots were fired in broad daylight, Clark said.

"That could have hit an innocent kid, that could have hit an innocent person, so we really need whatever help we can get to get these individuals off the street," he said.