Barbara Wein Allen implicitly trusted her employees — until she found out that one of them had stolen some $250,000 from her firm, Multi-Point Communications of Birmingham, Ala.

She isn’t alone. A dishonest or incompetent staffer, particularly one who holds a strategic management position, can cause devastating losses to a small business through embezzlement, incompetence, or negligence.

To better protect yourself and your company, here are four tips for vetting key employees during the hiring process.

1. Don’t depend on a cursory internet search. Consider bringing in a professional investigator if security is a real concern. When it comes to searching public records for red flags during the hiring process, there is no “one-stop shopping,” explains David Watts, a principal investigator for Allied Business Solutions, in “Due Diligence: Knowledge Is Power,” an article for a Florida-based legal magazine. Watts says the thousands of disparate court systems in the U.S. — both municipal and district — “do a poor job of contributing” to one another’s record systems. He also recommends that employers check with their state’s Department of Motor Vehicles to suss out any evidence of substance abuse.

2. Conduct background checks via phone calls. Checking references via phone versus submitting a form request typically nets more data — particularly negative data — than what is reported by former employers through reference request forms or letters. That’s according to the “Hiring Manager Toolkit,” an online resource published by the University of Virginia, in Charlottesville. Don’t wing it on the call. Instead, take a few minutes to collect your thoughts, after reviewing the candidate’s employment application materials, including his or her résumé and cover letter. Then, prepare a written list of open-ended questions to ask.

3. Beware of legal minefields. Don’t run background checks indiscriminately. Prying into a candidate’s life should be done with care to avoid subsequent claims of hiring discrimination. Discrimination claims investigated by the U.S. Equal Employment Opportunity Commission have mushroomed recently: The agency received 99,922 charges of discrimination in 2010 — a record high, notes attorney Susan Lessack inan article for Business Management Daily. Andrew Lu, who blogs for The Chicago Employment Law Blog, advises businesses to conduct criminal background investigations only when a job’s specific duties involve fiduciary responsibilities, such as handling currency or accessing accounting records.

4. Exercise caution with social media snooping. A 2010 survey by Jobvite — a recruiting software manufacturer in Burlingame, Calif. — shows that 83 percent of employers vet job candidates via social media websites. Although it’s true that people’s character flaws may be revealed on their social media profiles and news feeds, viewing Facebook pages may lead to claims of discrimination (see tip #3). For example, passing over a candidate who recently announced her pregnancy to friends online might result in claims of unfair hiring practices based on personal information.