I came into recruiting when good old, shoe-leather detective work was more the rule than the exception. So I’ve got a few offline headhunter tricks up my sleeve whenever I need to reach deeper into the talent pool in order to fill my jobs.

The first thing to remember is that the best source of information is always the hiring manager. Some recruiters will say that they don’t have access to the hiring manager, but I’ll bet if you ask nicely and explain why a brief conversation is necessary, you’ll get an audience.

There's lots of questions you'll want to ask, so be sure to make a list. If the hiring manager is unable to answer these questions, you might see if he or she can point you in the direction of someone who can.

Number one, ask which companies or organizations the hiring manager’s company has hired from in the past to fill a similar or related position. Then ask if there are any companies that could be a source of appropriate candidates. In other words, you’re looking for candidate breeding grounds. Add the names of these companies to your call list or list of keywords.

Now ask if there are any people—peers, associates, customers, strategic partners, college professors, etc.—who might be source of information, with respect to players in your field. What you’re looking for are what I call referral sources. Add these names to your call list. Make sure to ask for phone numbers and whether it would be okay to use the hiring manager’s name as a means of introduction. Also ask if there are any schools, governing bodies, trade groups, professional societies or other entities involved in the training, licensing, regulating or certifying of the types of people the company wants to hire. Add these to your list of keywords.

Then ask what publications—online or offline—the manager subscribes to or browses that might contain articles, information or buyers guides of interest to the targeted talent community. These are additional candidate breeding grounds, so you should add them to your list of keywords.

Finally, be brave and ask if the manager knows of anyone in particular who might be a good fit for the position you want to fill. Maybe he knows someone from word of mouth, or from a chance meeting a year earlier. Or, maybe he interviewed a candidate two years ago, and the person wasn’t a good fit then, but might be now. Or someone he offered the job to, but turned it down. Don’t assume the manager will clam up. If you’re really feeling frisky, ask if you can speak to any of the candidates he might have already interviewed, but has rejected, and who are no longer under consideration. That way, you can ask for their referrals. You might also want to ask if there are any candidates or companies you should avoid in your search, so as not to waste your time.

The One-Degree-Of-Separation Candidate
Here’s a technique I’ve used with great success. Now that you’ve identified an additional five to ten companies or organizations that might serve as candidate breeding grounds, pull every candidate’s resume with that employer’s name on it. But in addition to contacting the candidates who are currently employed at the target company, separate out the resumes in which the candidate used to work for that company, but is no longer there.

Now, pick up the phone and call that company. When you get a hold of the operator, ask two things. First, ask to speak to the candidate. “Oh, he’s no longer here,” the operator will say. “Really?” you say. “Do you know where he is?” And when they tell you, write it down. If they don’t know, ask, “Is there anyone in his department who would know where he is, or how I can reach him?” and get that person’s name and direct dial number. Make a note: That person is now a passive candidate or referral source.

Next, you ask, “Do you know who’s taken his place?” and add that person to your call list, either to recruit directly, or to interview as a referral source. If the operator doesn’t know who’s taken his place, ask who you would talk to who would know.

Remember, your best candidates are often a degree of separation away, in which case it might take a phone call or an email or two to track the person down. I’ve found that the people who are most helpful in your search are those who can refer you to folks where they used to work, not where they’re currently employed.