Determining who the person you are investigating calls or texts on a regular basis is perhaps the single most powerful research tool in the amateur detective’s arsenal. Known in the private investigator trade as a “CNA” (Customer Name & Address), this basic detective function serves to connect the dots between people, places, and businesses.

The Reverse Phone Lookup is what it’s commonly called today, and regular people now use it everyday to snoop on their kids, or bust their spouses. Variations of the reverse phone lookup are offered by hundreds of different vendors all competing to catch a slice of this tremendously popular market. In most cases, the only effort (apart from a nominal fee) on your part is to enter the phone number in a search box like the one below: