Data from man's ankle bracelet led police to charge him as an armed home invader, but court says that was unconstitutional

In 2015, a man wearing a GPS device as a condition of bail on a Boston drug charge was arrested for an armed home invasion in Medford after police there asked the operators of a state GPS database if anybody in it had a GPS pinged from the location of the home invasion and his info showed up.

But the Supreme Judicial Court ruled today that prosecutors can't use that data because the police didn't have probable cause to query the database, in a decision that also sets limits on the ability of judges to order people awaiting trial to wear the devices.

In July, 2015, Eric Norman was arraigned as a repeat cocaine dealer in Boston Municipal Court. As a condition of his bail, the judge in the case ordered him to stay out of Boston - except for court appearances - and ordered him to wear an ankle bracelet so that officials could make sure he wasn't violating that order.

The next month, Medford Police, investigating an armed home invasion contacted the state probation service and asked it to check its GPS database to see if there were any pings from the time and location of the home invasion and Norman's data came up.

Big mistake, the state's highest court ruled today. That sort of query is legally a "search" and a search requires some minimal probable cause without a warrant. And in this case, police had no reason to believe Norman was involved, they didn't even know who he was at that point and so no probable cause to ask Probation to do a general query and see what popped up - and that could mean trouble for the rest of the Commonwealth's case, which included a witness ID that only came after police got back the results from the state database.

More generally, the court cast shade on the use of GPS devices as part of bail conditions. The court said that the point of bail is to ensure defendants return to court and that GPS devices don't do that. State law does grant exceptions in certain cases, such as domestic abuse, but Norman's drug charge was not one of the crimes covered by exceptions, and so it's unconstitutional to require people who have yet to be convicted of a crime to be burdened with what is essentially a form of punishment and a restriction for people who have.

When a judge orders GPS tracking, a "modern-day 'scarlet letter'" is physically tethered to the individual, reminding the public that the person has been charged with or convicted of a crime. Commonwealth v. Hanson H., 464 Mass. 807, 815-816 (2013), quoting Commonwealth v. Cory, 454 Mass. 559, 570 n.18 (2009). See Commonwealth v. Goodwin, 458 Mass. 11, 22 (2010) ("ankle bracelet . . . may . . . expos[e] the [individual] to persecution or ostracism"); Commonwealth v. Raposo, 453 Mass. 739, 740 (2009) (describing "ankle bracelet, which is permanently attached to the probationer").

If a GPS monitoring device loses connection with either the cellular network or the satellite network, or if the device's battery runs low, "alerts" from ELMO [the state office that monitors GPS signals] are issued. ... The individual may have to leave his or her location in search of a signal, or may be required to travel to a location where the device can be charged. ... These frequent interruptions can endanger an individual's livelihood. ... Lastly, GPS monitoring can place an especially great burden on homeless individuals. See Commonwealth v. Canadyan, 458 Mass. 574, 575, 578-579 (2010) (noting "undisputed evidence that homeless shelters" could not provide electrical outlets necessary to charge GPS units).