I hate to say it, but these days it pays to be careful, whether hiring a babysitter, going on a date, or entering a business partnership. Inquiring minds want to know: Does this guy have a criminal record? There are a number of online resources where you can check a person's background at no charge, and identify criminal records, prison time, sexual offender status, and other important information. Start with CriminalSearches.com and other people-check resources.
Need more information? Newspaper archives are one of the best online research tools.