Any experienced investor or manager will tell you if you see 1 dead roach your home is already infested. 

Just after the "myth" that "off market" properties are "good deals"....when it's more likely they're an over priced, issue infested, lien ridden, liability.

Then to walk through them, we experienced alot of termite infestations (which isn't uncommon for AZ, but just surprised us that it was left untreated), and missing pipes and electrical. 

In the past it’s been infested with gangs.

The one thing HUD specializes in is running drug infested slums - you can see that everywhere in the USA!

In my case there were two problems that took a little time to work through: 1) They had a clause which stated that all exterminations for bug infestation were my responsibility during the lease and any loss of rental furniture/housewares provided for the tenant resulting from infestation would be covered by me.

If you have the cash to deal with:  A house that has had too many animals, either pets or infestation, Mold / Grow operation, Squatters/ human waste/ house stripped of all copper plumbing and wire, Caveats/ liens against the property that have to be paid prior to change of title, and afterwards not be financially ruined then go for it. 

I'm still looking into at what cost to fathom ever buying this even as an investment lol ... really I agree with people like @Jeanni Prescan regarding this specific property (that doesn't mean I will always run away from all crime infested areas though), but I'm just checking my gut feelings in the numbers on this one.

I've fogged the house with several different solutions for this as well.Rats had definitely infested the attic and the garage at some point before I owned the house.

Crime and drug infested in a couple years.