Supreme Judicial Court (July 1, 2010)
Records from a global positioning system device (GPS) are sufficiently reliable to be admitted into evidence in a defendant's probation revocation hearing.
The defendant plead guilty to various offenses including domestic assault and battery. As part of his probation, the judge ordered the defendant to stay away from the victim and to submit to electronic monitoring by a GPS device. The defendant violated the terms of his probation by going "out of range" on more than one occasion. At the probation revocation hearing, the chief probation officer testified to the facts of the specific violations and introduced records from the GPS device. The records consisted of computer generated maps, superimposed with a representation of the defendant's location at the times and on the dates indicated, and activity reports which documented the defendant's location at certain times, and his communications with the GPS monitoring staff. The judge found the defendant had violated the terms of his probation based on the GPS records he found to be "substantially trustworthy and demonstrably reliable."
The defendant appealed from the revocation of his probation. The Appeals Court affirmed the judge's decision, holding that the GPS records were not hearsay, and thus admissible, or alternatively, that they were admissible as business records. The SJC granted the defendant's application for further appellate review.
The SJC's 1990 decision on Commonwealth v. Durling sets out the evidentiary requirements for probation revocation hearings. The evidence presented at a probation revocation hearing must be reliable. If the evidence is admissible under standard evidentiary rules, it is presumptively reliable. If it is not admissible under such rules, a judge must independently evaluate its reliability. While unsubstantiated and unreliable hearsay cannot be the entire basis of a probation revocation, evidence that bears substantial indicia of reliability and is substantially trustworthy can be. Regarding the GPS records at issue in this case, the SJC found them to be, "… factually detailed and made close in time to the events in question by persons reporting to the probation department and responsible for monitoring and communicating with the defendant. To the extent they rely on GPS technology, that technology is widely used and acknowledged as a reliable relator of time and location data." Thus, the SJC ruled, GPS records are sufficiently reliable to serve as the basis of a defendant's probation revocation hearing.
Note: The Court cautioned that in the future GPS records offered in revocation proceedings "should be properly attested and certified by an appropriate custodial officer."