>> reporter: once again, police raced through the streets of quiet coronado island. and once again, their destination was the mansion on ocean boulevard. jonah's girlfriend rebecca was staying there. jonah's brother adam had spent the night in the guest house. >> you wake up. you walk out. tell me what you see. >> a woman hanging. at the time, i didn't necessarily think to myself, "oh, my goodness, she's bound," or whatever. but just rebecca's hanging. >> reporter: naked, bound hand and foot, rebecca zahau was hanging by the neck from a second-floor balcony. >> i said i guarantee you, my heart started racing. this is actually happening. >> okay. how old is she? >> i'd say about 30. >> 30? okay. when was the last time you saw her? >> last night. >> reporter: even as he called 911, adam says he thought she was dead.