@Jacob Beg gut feeling goes a long way. Always go with the gut.
I had one prospective tenant show up, a nice family, everyone was dressed up nice, even the kids. But too nice. Like the kids were wearing suits and a bowtie, it was super cute, but a little weird. Then the husband turned out to only be a "friend" who was helping her out. Then when I called her referral something seemed off. It was too good and too casual, like he was expecting my call. Did some digging. Looked on google maps at her previous/current address (which was not in such a good part of town). On street view as pure luck would have it, I could see a "for rent" sign on her building and the number was not the same one she gave me. People change numbers I thought, and the building could have been sold since. But I decided to call just in case. Turned out this was the REAL number for her landlord and this poor lady started to vent about how she hadn't paid rent in months and she's trying to get rid of her! She told me not to touch her with a 10ft pole. Long story short my gut feeling had been telling me from the start that something was off, and it turned out be right. I always trust my gut.