THE BRONX - Police are investigating several robberies at a Bronx senior citizen complex after receiving reports that jewelry and cash were stolen from residents' apartments. Investigators say the incidents took place over the span of a week at the White Plains Road facility. They say nine tenants claim to have been burglarized, with some losing chains, rings and as much as $300. "I noticed it was gone," says Raphael Alvarado, referring to his wife's bracelet. "And my bracelet, it was gone. And that's when I noticed somebody must?ve came in with a key." In response to the burglaries, building management officials say they intend to fully cooperate with the authorities. They say they have no reason to believe the incidents are attributed to any building employee. All tenants who had their belongings stolen say they will soon replace their locks. They also signed a petition to cover the costs of the locks, which they plan on giving to the management company.