In digging into the details through public record searches I find out that he has had 3 evictions, several drug convictions, and a violent crime.

If they are afraid of a violent confrontation, then they can call the police for an escort.

We do not rent to anyone that has failed to pay rent, been evicted, or has a violent crime conviction. 

I am not talking to this person directly because from my past experience (when I had to call cops on him) he seems to be a violent person and I am concerned for my safety.What are my options to deal with this situation?

“A good plan, violently executed now, is better than a perfect plan next week” — George Patton

We just stay away from violent crime areas but are realistic that crime does happen in some of our neighborhoods. 

asked them pls. cite them, they said on phone, we have to come to your home & you sign complaint & face him/them in court. l'm 77yrs.old sick, as is my husband is, they want us to deal w/potentially violent men, who yell 'Go live in Leisure World then' They said to us when we first moved in & politely asked them to go inside we cannot sleep, 'Were not used to Neighbors', so because we rent we have NO RIGHTS?'

Their job base is very solidly diversified, the evidence of which came several years ago when the oil prices shot up, then down violently.

One's chance of becoming a victim of either violent or property crime here is one in 26.Is this a bad place to invest?

This is the worst area, violent crime-wise, in the entire City of Riverside.