There are often times when police officers have to rely on anonymous callers who dial 911 to tip police off on a crime they had observed. Whenever a defendant is arrested as a result of such a tip, the trial court must determine the caller’s reliability before allowing the case to proceed to trial. In the case of Com. v. Depiero, the Appeals Court determined that it was lawful for police to arrest a driver with a history of drunk driving after receiving an anonymous 911 call reporting erratic driving.

The 911 Call
Police dispatch received a call stating that a “drunk driver” operating on Memorial Drive was “swerving all over the road.” The caller did not identify him/herself, but did provide the dispatcher with a license plate number, make, and model of the car. A state trooper was then dispatched to the driver’s address, where he observed the driver pull into his driveway. After the driver parked, the officer turned on his emergency lights and conducted a traffic stop. The driver admitted to having drunk alcohol, and subsequently failed the field sobriety tests.

Arguments Before the Court
The issue before the court was whether the trooper conducted the stop on an unlawful basis, in violation of the driver’s Fourth Amendment and Article 14 rights. The driver’s argued that the trooper had not observed any indication of erratic driving to suspect that the driver was intoxicated. In fact, the trooper testified that he observed the driver operate the vehicle normally and without incident as pulled into his driveway. The State argued that the police were entitled to rely on the anonymous tip provided through the 911 wall, and that the tip was sufficiently reliable to give the officers reason to suspect that the driver had been operating under the influence.

The Aguillar-Spinelli Test
Massachusetts courts have adopted the Aguillar-Spinelli test to determine whether an informant’s tip is reliable. The test has two prongs. First, the court looks to determine whether the caller had a sufficient basis of knowledge to support his reports. The court then looks to whether the call can be deemed credible; i.e. whether the caller can be trusted to give accurate reports. Credibility can be established by either the police corroborating the tip through their own observations of the defendant’s conduct, or through other indications reliability.

Here, the information provided in the call established the caller’s basis of knowledge because the information suggested that the caller had just observed the erratic driver first-hand. As to the caller’s reliability, the court held that the judge could infer from the caller’s report that the caller had dialed 911 in response to the shocking event that the caller witnessed. There was no reason to think that the caller was trying to falsely accuse the driver. This report, coupled with the officer’s knowledge of the driver’s past criminal history, made this arrest reasonable.

The important point to take home from this case is that police officers are given wide latitude to use information collected from many different sources to justify an arrest. The best way to challenge these arrests is to challenge each source of information, and the actual information communicated through these sources. The court’s analysis in this decision is consistent with the Massachusetts Supreme Judicial Court’s own decision in Com. v. Anderson, as well as the U.S. Supreme Court’s decision in Navarette v. California. Together, these decisions establish greater bases for officers to stop and arrest individuals based on anonymous tips.