You are exposing yourself to potential liability (neighbors with kids) and damage to your business (that guy rents to sex offenders/drug criminals). 

I've already given drug screens to 5 people going there for work. 

I once had a perspective tenant apply looking professional and nice, while on social media we could see what type of lifestyle he led (non stop partying and drugs)   You need to be careful why you say no, but finding red flags can sure help narrow down the search. 

I flip vacant land properties and by all means I am classified as a "real estate dealer". 

Its the gate way drug to owning mobile home parks in the near future.

Its the gate way drug to owning mobile home parks in the near future.

Try telling a blackjack dealer you should get your bet back when you only have 1 less point than them.

The layout isn’t great and the neighborhood still has its quirks (drug dealing, theft, airliners flying right overhead).

Proceed with caution if you are looking are purchasing this property has things may have happened i.e. demolition, drugs etc....

It's the murders, drugs, rape, car jacking, home invasion type stuff that can be more alarming as a percentage of police calls and activity to an area.