like- pinching myself- i ve got to wake up from this dream. this has gotta be a dream. i think our whole world just changed. reporter: a short time later, stephen s sister, kim, got a knock too. i remember runnin into the bathroom and getting sick. and i was kind of i couldn t do anything. reporter: heidi s boyfriend stephen, meanwhile, had been down at a police station the whole time being interviewed. officers snapped this picture. his clothes bloodied he said from trying to perform cpr and then cradling heidi s bleeding body. now, how much did you know about him or the victim by that point? really a lot. we just knew they were in a relationship. the relationship was good. reporter: husbands and boyfriends are always persons of interest, but homicide investigators say stephen was cooperative. he told them how after his shift ended at a local lowes, he picked up heidi from her job in the car they shared a 1994 red honda civic. it was 5:45 pm, he thought, when he dropp