You're doing the right thing. Keep calling the police.
You can try to call Department of Building Inspections to see if they can send someone over to check the property to see whether it is unsafe or some other defective issues.
You can get in touch with the office of your district Supervisor to see what they can do to help.
The only thing you can do really is to make a lot of 'noise' about it to force the landlord to be more proactive in keeping the property secure. How many units are in the building? I forget the number but past a certain amount, they need to have a resident manager on site.