Interested in investigating a few different real estate avenues.

I have no reason to believe there was any foul play involved - but really I am in the dark about exactly what happened (I reached out to the detective and gave my contact info, but since its an ongoing investigation, they can't tell me anything).  

Folks here have provided suggestions to investigate.  

I am sure you investigated it all, I am just curious as to the rationale of the building department.

The 1% rule is merely a guideline that some investors use to screen properties to see whether they care to investigate further.

If the seller's numbers vary greatly from those figures you should investigate further.

Are there any general screening check lists or math formulas that can give me a general idea if I should spend time further investigating that property or move on to spend my time on another property? 

My dad has been an investigator for 30+ years, looking to retire soon and I think he could provide a great service helping to find these people.

Others are quite legitimate, those are the ones you should investigate.  

I have spent a lot of time investigating the topic and stumbled across BP and was drawn to the amount of information on it.