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. 

They respect the property because they are your friend, or they routinely expect special treatment from you because they are your friend.  

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.

I’d run like a bat out of hell from a lagoon or a water treatment plant , though.Again, it is best to get some input from an experienced operator but consider this:  if a newbie who has just been reading books and listening to podcasts can pinpoint red flags, you know that’s a deal to run from.  

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.

Avoid anyone with sex charges or with anything violent in their criminal records....no matter how long ago they assaulted someone or with drug charges.