Someone broke into my house, but didn't take anything. Do you think they'll come back? ?

Someone broke into our house when I wasn't there. My parents came in though through the garage as it was happening and the robbers got away through another door, but didn't take anything. Do you think they'll be back to actually take something? I can see footprints from where they were in the house on the carpet, but I just find it strange that nothing was actually taken.