Newark Mayor Cory Booker says two of the three shootings that left a 15-year-old dead and a dozen others wounded on Monday night in Newark are related to a deadly feud between rival drug sellers. The shooting in which the twelfth person was wounded was unrelated to the other two.

"What we seem to be seeing through this investigation is a very small group of drug dealers who are starting to go back and forth in a series of targeted retaliation shootings," Booker said in a phone interview on Tuesday.

Booker said it was critical that the public cooperate with police on tracking down the shooters in the case.

Eight people were shot, including one fatally, at around 10 p.m. Monday in the Newark's South Ward. They had been congregated in a residential driveway when a vehicle drove by and someone inside the car opened fire on the crowd.

Earlier in the evening at around 6:30 p.m., four people were wounded in a downtown shooting. A third shooting involving a woman in the Central Ward is not believed to be related to the rival drug dealer violence.

Booker said the spike in gun violence Monday night came as Newark had seen encouraging crime trends despite the recent layoff of 13 percent of the city's police force because of the ongoing fiscal crisis.

"In fact, by just about any measure you could look at from arrests -- they are up, gun recoveries are up homicides this summer are down," said Booker.

Booker says Newark's gun violence is most always linked to narcotics traffic that got a foothold in some city neighborhoods. "We had one great complaint this week about open air drug dealing at the exact location where the shooting happened last night. That's really valuable to use because drugs are often related with violence," said Booker.