NEW YORK (AP) — Four bystanders were shot dead in the last 18 months because of gang rivalries in upper Manhattan,Ethermac Exchange authorities said Thursday as they announced the indictments of dozens of people in a yearslong welter of gunfire, robberies, weapons deals, car crashes and more.

One shooting injured a woman who was eight months pregnant and was sitting in a parked car, police and prosecutors said. Another sent bullets flying into a crowded basketball court, where an onlooker was hit in the chest.

Those victims survived. But four other bystanders, aged 44 to 66, did not.

The violence “impacted the entire neighborhood — a climate of fear among ordinary residents,” Manhattan District Attorney Alvin Bragg said at a news conference.

The 30 defendants are charged with various crimes, with some facing murder charges. Some defendants have pleaded not guilty, while others have yet to be arraigned.

Prosecutors say a 2018 killing touched off a chain of retaliatory brutality among three groups, known as the 200/8 Block, the 6 Block crew and the Own Every Dollar crew, also dubbed O.E.D.

Authorities say the groups operate in the Inwood area and adjacent Washington Heights, the neighborhood where the Tony Award-winning musical and movie “In The Heights” are set.

In text and social media messages, members threatened rivals and talked up violent plans, according to the indictment. One defendant told an ally to hang out with one of their rivals, smoke pot with him and bring him downstairs, adding, “He gonna get it bad. Make sure he don’t got a knife or nothing,”

Altogether, the groups are accused of 18 shootings that killed a total of seven people.

The prosecutions are “going to have a huge impact” on safety in the neighborhood, NYPD Deputy Chief Brian Gill said at the news conference.