Suspicion of infidelity or a desire to exit a relationship often creates a motivation for a person to spy on their relationship partner. The results can provide peace of mind that their worst fears of an unfaithful partner are true, or give them confidence that their decision to leave the relationship is valid. “People are dying to know if their spouses are cheating,” said Randall Kessler, past head of the American Bar Association’s family-law section.

Private parties should be careful in the methods used to obtain information on a spouse. Federal and state laws govern the protection of privacy and can create legal liability for eavesdropping, voyeurism, or stalking. As the techniques and technology being used become more robust, adhering to the law is more important. At least five of the 13 U.S. circuit courts have found that the Federal Wiretap Act does prohibit surveillance within marriages. “In one 2011 Nebraska case, a mother who embedded a listening device in her daughter’s teddy bear to record the girl’s father was found guilty of violating the Federal Wiretap Act. And in a 2008 Iowa ruling, a court found that a man had violated his wife’s privacy by taping her with a camera surreptitiously installed in an alarm clock in her bedroom in their home.”

The liability does not stop with electronic recording. GPS surveillance is a booming trend. A Minneapolis man was convicted of sticking a GPS tracker on his wife’s car. “Pretty amazing stuff,” said Mr. Hormann, a former investment salesman and now a truck driver. At least four times in late 2009 and early 2010, he used it to locate his then-wife, Ms. Mathias, court records say. In July, 2010, a jury convicted Mr. Hormann of two charges, stalking and tracking the car. He spent 30 days in jail.

A licensed private investigator should be aware of all GLB, DPPA and local laws so that appropriate spousal monitoring does not turn into a stalking conviction. Also, evidence gathered by a licensed third party is more likely to be admissible in the divorce proceeding. Pictures or data gathered by an adversarial spouse directly may be excluded due to bias or to an improper chain of evidence.