Forward-backward multiplicity correlations have been measured with the STAR detector for Au+Au, Cu+Cu and {it p+p} collisions at $sqrt{s_{NN}}$ = 200 GeV. A strong, long-range correlation is observed for central heavy ion collisions that vanishes in semi-peripheral events and {it pp} collisions. There is no apparent scaling of correlation strength with the number of participants involved in the collision. Both the Dual Parton Model and the Color Glass condensate indicate that the long range correlations are due to multiple parton interactions. This suggests that the dense partonic matter might have been created in mid-central and central Au+Au collisions at $sqrt{s_{NN}}$ = 200 GeV.