Supreme Judicial Court, June 5, 2013

A “mere passenger” of a vehicle has no possessory interest in the vehicle and therefore the government’s actions of attaching a global positioning system (GPS) device on the vehicle are not a seizure of his property.  However, ”even in the absence of a property interest, the government's contemporaneous electronic monitoring of one's comings and goings in public places invades one's reasonable expectation of privacy.”  “[U]nder art. 14, a person may reasonably expect not to be subjected to extended GPS electronic surveillance by the government, targeted at his movements, without judicial oversight and a showing of probable cause.”  The Court did not decide how broadly such an expectation might reach and to what extent it may be protected, but the fact that the police monitored the defendant over a thirty-day period was sufficient to establish that he had standing to challenge the validity of the warrant.