UCR data is published annually by the FBI.UCR data is reported as either violent or property crime, which then break down further into eight possible sub-crime categories.

I look at crime maps online and percentage of violent to non-violent crimes and frequency trends.

Our rental policy currently excludes violent felony convictions so he isn't excluded on the misdemeanors however I'm concerned that he was not forthcoming with this information.

More troubling than the price drop, however, was the sudden paralysis in the market as buyers and sellers violently disagreed about fair clearing prices and transactions tumbled 40.4% to 5,921, the biggest year-over-year decline since 2009, led by the detached market segment.http://www.zerohedge.com/news/2017-08-03/toronto-h...

However, violent crime rates continue to rise and that scares me as an investor.

Freddie and Fannie will look at crime reports for that area, if their is a significant amount of "violent crime" they tend to try and shy away or limit their exposure on a case by case basis. 

According to bestplaces.net, we have a slightly lower violent crime rate here (38.5 vs 42.6 for Port Huron) and a slightly higher property crime rate (46.9 vs 39.5).

IDEAS: abuse of common areas, theft of personal & common possessions, violent behavior, assaoult of another roommate, general friction over kitchen, bathroom, laundry, storage, parking, etc.You may want to create a new post: "What issues have landlords had with rent-by-room tenants?"

As far as having someone move in they seemed very low income therefore, I was afraid it may get violent.

Violent crimes--Car jackings, Murder, Rape, Armed Robberies, and places with (a lot of) lesser crimes.