Talk to taxi drivers and police officers while there. 

Do I need to turn it over to the police?

If she was really scammed, she would have called the police and you would be contacted, because you know who your previous tenant is. 

I am the second call on most of my properties (the ones in C neighborhoods)--this way I can call the police as well (which has only happened once, when the property was vacant).  

Preferably when they are not home but if you are worried you can request police presence.

I have called the police twice because of her ugly actions.  

Under Washington law possession descends to the current possessor from the time his or her non owner predecessor commenced possession. 

Also, police don't do background checks for the general public.As common as my name is, my birthday also happens to be one of the most common.

PM or tenant applicant as a landlord/owner it is your responsibility to screen and police everyone from the beginning and on a ongoing bases.

He said he did not and I had to call someone to bring cash or was going to call Police.I told him I will call Police for him and save him the trouble.The Police told him over the phone that the money is legal tender and he has to accept it.He wasn't happy but took the money......