My first experience with conventional lending last year was down right ridiculous and now that I think about it possibly criminal.

I'm looking for a website to help screen tenants (credit, eviction, and criminal reports).

We do extremely thorough vetting so that includes criminal background, employment/income verification, rental history and credit.  

—In all criminal cases, contempt cases, and other cases filed pursuant to this chapter, if a party has sold, leased, or let real estate, the title to which was not in the party when it was offered for sale, lease, or letting, or such party has maintained an office bearing signs that real estate is for sale, lease, or rental thereat, or has advertised real estate for sale, lease, or rental, generally, or describing property, the title to which was not in such party at the time, it shall be a presumption that such party was acting or attempting to act as a real estate broker, and the burden of proof shall be upon him or her to show that he or she was not acting or attempting to act as a broker or sales associate.

Please keep in mind that there is statute of limitations in each individual State for any criminal offence committed in the past.

He has sent a copy of criminal background check from his home country saying no records of criminal history found ... not sure how much weight that carries.

My night job is a winged superhero protecting Gotham City from criminals. 

His criminal and credit history are borderline but passable.He says that he really wants to buy the whole duplex but would like to rent one of the apartments for a year first.

Further, that there were entire courses and clubs dedicated to teaching these criminals how to con you out of your house, your money, and your first born child and run away before you knew what hit you.

For a criminal background check, go back 5 or 10 years.For residential history, 3 years should be fine.If someone is starting a new job when they come to town, I verify their current and last employer and call the company that just hired them to make sure they actually have a job.