Then on Sunday, Vincent Depippo, 42, and his nephew, Neil Nasto, 21, both reportedly associates in the Colombo family, were shot in their parked car in Bath Beach. Law-enforcement officials say that the killings had all the marks of a mob execution.

Most victims in the violence were low-ranking mobsters, but some have been innocent bystanders, and some businesses have closed because of the violence. In late November 1991, three people were injured, including a 4-year-old girl, when they were struck by a car driven by a man fleeing a mob ambush in Bensonhurst.

Days later, Matteo Speranza, an 18-year-old cashier, was gunned down behind the counter of the Wanna Bagel store at 8905 Third Avenue in Bay Ridge. The police concluded that Mr. Speranza was killed by mob executioners who apparently had intended to kill another store employee.