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 dropped her off at their home. it was, he said the last time he saw her alive. the detectives put together a timeline for the boyfriend who'd run a bunch of errands after dropping heidi off.