Law enforcement often engages in creative strategies to catch suspected criminals. Sometimes, especially when surveillance happens without a warrant, these efforts violate suspected criminals' constitutional rights.

If the suspect's criminal defense attorney is able to prove that a police action violated the constitution, the evidence obtained from that action will not be admissible in court.

The rules regarding constitutional search and seizure evolve as technology changes. Earlier this month, the Supreme Court of the United States ruled that it was unconstitutional for police to place a GPS tracking device on a suspect's car without a valid warrant.

Surveillance Violated Protected Property Interest

The case centered on Antoine Jones, a Washington, D.C. nightclub owner. Police suspected that Jones was part of a cocaine trafficking ring.

Although they did not have a valid warrant, the police installed a GPS tracking device on the underside of Jones' car. For more than a month, they tracked his every move. Ultimately, the evidence was used to convict Jones of conspiracy to sell cocaine.

Jones and his defense lawyer challenged the conviction, arguing that the use of a tracking device violated Jones' constitutional right to be free from unreasonable search and seizure.

The case went all the way to the Supreme Court, which ruled in Jones' favor. In the majority opinion, Justice Antonin Scalia reasoned that the police's use of the device represented more than just mere observation of Jones' activities. Rather, "the government physically occupied private property for the purpose of obtaining information."

Generally, issues of constitutional search and seizure hinge both on property rights and the idea of a "reasonable expectation of privacy." Notably, the Court did not address the issue of whether Jones had a reasonable expectation that his travels would remain private.

The decision does not constitute a blanket prohibition on law enforcement's use of GPS tracking devices. Rather, it simply requires police to obtain a warrant before installing the devices.

Source: New York Times, "Justices Say GPS Tracker Violated Privacy Rights," Adam Liptak, Jan. 23, 2012.