Hyde and Jekyll - Who kills who

In the end one point is made clear Henry Jekyll/Edward Hyde is dead. Although how did It get too that point? Was it finally Jekyll deciding he must rid the world of Hyde by taking his own life? Or perhaps Hyde wanted the ultimate control, killing Jekyll and himself in the process? The struggle for control was a recurring theme throughout the whole novel, yet ironically the one thing most desired was just out of reach for both men. Jekyll thought having Hyde would create a sense of control, something he once lacked. Although by creating Hyde, Jekyll lost grasp of reality. He thought change would be the answer, yet all change did was give Jekyll a new perspective on life heading him into a new direction. This is why I believe Jekyll killed himself riding the world of Hyde in the process. “I am careless; this is my true hour of death and what is to follow concerns another than myself. I lay down the pen and proceed to seal up my confession, I bring the life of that unhappy Henry Jekyll to an end.” In the end Jekyll got the control to kill himself taking matters back into his own hands; thus ultimately reaching his main goal right before decease.