We don't know for sure what the time of death was. They might have already had time to hide it. [ ... Maybe that was a little overly pessimistic. ]

But checking bathrooms would be a start. There's no way someone could have stabbed someone without getting any blood on them. [ His tone is thoughtful but straightforward, and wastes no time in lamenting the turn of events. It's a terrible thing, but what's important now is to catch the killer. ]