So. A character in my screenplay is murdered in the first scene, and he has no known next-of-kin. Would the police detective need a warrant to search his apartment for clues, or would the permission need be given only by the landlord? Any help would be absolutely appreciated. Thanks!
They don't need a warrant to search a crime scene. Warrants are to protect people who might be charged with a crime from having
their own property searched; the victim's property can be searched without a warrant, since searching it doesn't violate
the suspect's constitutional rights, and the victim's rights aren't violated by such a search because (1) he/she is not a suspect in any crime (the search isn't being done to find evidence against
the victim), and (2), more importantly, he/she is dead. So basically, warrants are for searches of places other than the crime scene. So if they want to search a suspect's apartment and the suspect won't consent, they need a warrant. In this case, say the handyman was a suspect; if the handyman has a workshop in the apartment building the landlord can probably just consent to that search, since the workshop isn't something the handyman leases, it's just where the landlord keeps all the tools and whatnot that the handyman needs for his job. So they could search that with just the landlord's consent. But if the suspect has an apartment there, with a regular lease and his own key, then they need the suspect's consent (or a warrant); the landlord's consent wouldn't suffice.
Things get slightly (but not very) complicated when the crime scene IS the suspect's property, such as where someone is killed in their home and their live-in partner or spouse is a suspect. But it doesn't sound like that's your situation.