The police swarmed Co-op City, the Bronx housing complex, at 8AM with reports of a triple shooting. It turned out that a disgruntled former employee shot and killed an employee in a basement office and then shot two other people on his way out.
The shooter, identified as 50-year-old Paulino Valenzula, surrendered after the shooting; the NY Times reports he "took a bus to the Bronx Criminal Court building" where he turned himself in. Valenzula was fired from his job a year ago but sued to get his job back, but lost that case this week. Co-op City is managed by the Riverbay company.
Co-op City is the largest cooperative housing development in the world - it even produces its own power. It was built on top of the former amusement park Freedomland and opened in 1968.