This paper proposes a novel dynamic slicing technique for object oriented concurrent programs. We introduce the notion of Object Oriented Concurrent Program Dependence Graph (OOCPDG). Our dynamic slicing technique uses OOCPDG as the intermediate representation and is based on marking and unmarking the dependence edges as and when the dependences arise and cease at runtime. Our approach eliminates the use of trace files and is more efficient than existing algorithms. Besides, it encompasses different aspects of object oriented programming paradigm viz. inheritance, polymorphism from the slicing arena. It can handle dynamically created object based processes. It can also handle process interactions through shared memory and message passing. The updating to the intermediate representation is truly concurrent. Multiple processors execute different object based processes concurrently and require special handling. We also report a dynamic slicing tool called CDSOOCP (Concurrent Dynamic Slicer for Object Oriented Concurrent Programs) which implements our dynamic slicing technique.