 Midway through season three , Kate persuades Rousseau to help some of the survivors find the Others ' home , by informing her that Alex helped her escape from the Others . When they arrive , Rousseau abandons the group and watches from the bushes as Alex walks past . A few days later , Rousseau leads the survivors to the radio tower in order for them to contact a nearby freighter . En route , they encounter Ben and Alex ; Ben explains to . Season four begins with the survivors dividing into two groups , with those who believe the people from the freighter to be dangerous , including Rousseau and Alex , joining Locke ( Terry O 'Quinn ) . After learning of the freighter crew 's intentions to kill everyone on the island , Ben directs Rousseau , along with Alex and her boyfriend Karl ( Blake Bashoff ) , to head to the Temple where the rest of the Others are located . On their way , Rousseau and Karl are shot by unseen attackers , and both are killed . The buried bodies of both are discovered by Miles ( Ken Leung ) , Sawyer ( Josh Holloway ) , and Claire after they leave Locke and travel back to the beach . 
