This isnt complicated.
I have a simple question for the OP:
Do you think somebody MIGHT be in danger?
There are three possible answers:
1) Yes (this is how I understood the OP)
definitely call the police. (Is there anyone, besides for Joseph, who disagrees in this situation?)
2) No – (I dont see how this fits with the OP)
I agree dont call the police. IF there is no chance anyone is in danger
3) I dont know
This response shows a misunderstanding of the the question was “MIGHT someone be in danger” if you dont know then the answer is Yes. See above for the appropriate action