Sure. But, wouldn't that evidence come from actually searching the shooters papers and effects. Then a warrant could have been issued for the victim if evidence presented itself. This is opposite. This is info based on the shooter; 'evidence or knowledge' she wouldn't know if she hadn't illegally entered his apartment.
Both...You’d never search one and not the other involved.
If they suspected I killed you, they’d search both of our places of residence. Or at least they should. That would include their vehicles, work places etc.
Another example would be the victim documenting or making notes on their laptop about being previously threatened by the shooter. That information would be extremely important to determine motive etc.