We are reaching out to the old original owner with the criminal history (involving ordering a hit on his partner which occurred unsuccessfully, an IRS agent and the mail man).

@Romeo Kaado how are you im currently planning on attending a real estate class for my liscence,but due to my criminal past im scared to lose my money because the real estate commission is not giving me a sraight answer.My history only consist of drugs distribution,no sex charges,no violence, no theft,no robberies,nore fraud.Will that disqualify me from getting my liscence because i cant really afford to lose 400$

From the info I've gathered, landlords can no longer have "blanket" policies on criminal history - no more saying any positive result is an automatic fail.

How do you screen without checking criminal history?

You are exposing yourself to potential liability (neighbors with kids) and damage to your business (that guy rents to sex offenders/drug criminals). 

The seller has the risk of the buyer not making the mtg payments and there is very little the seller can do about it.Proper state required disclosures need to be executed by the seller, otherwise the buyer has some legal/criminal liabilities.Once a sub2 is done, a short sale is no longer possible.

A few years ago I graduated from San Diego State with a bachelor degree in Criminal Justice and also got my master's degree in Homeland Security.

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. 

My current tenants which were inherited when I bought the property are moving next month..So now the real challenge of being a first time landlord is approaching, and my biggest concerns with screening are:Evictions and Criminal Background - How do you check for this?

You need to perform a credit, criminal & eviction check on every applicant.