In this work, a novel search strategy for autonomous search and rescue robots, that is highly suitable for the environments when the aid of human rescuers or search dogs is completely impossible, is proposed. The work area for a robot running this planning strategy can be small voids or possibly dangerous environments. The main goal of the proposed planning strategy is to find victims under very tight time constraints. The exploration strategy is designed to improve the success of the main goal of the robot using specialized sensors when available. The secondary goals of the strategy are avoiding obstacles for preventing further collapses, avoiding cycles in the search, and handling errors. The conducted experiments show that the proposed strategies are complete and promising for the main goal of a SR robot. The number of steps to find the reachable victims is considerably smaller than that of the greedy mapping method.