A trail of GPS “electronic breadcrumbs” showing the path that a cab took from Massachusetts' South Shore to the North Shore, and then to two Connecticut casinos, can be used as evidence against three men charged with killing a popular Ipswich, Mass., restaurant owner in 2011, a judge has ruled.

Jun Di Lin’s Boston Cab Associates taxi was equipped with a credit-card machine that periodically sent data about its location to the machine’s owner, Creative Mobile Technologies.

Even if the meter wasn’t running in the early morning hours of Sept. 27, 2011, the machine was silently tracking Lin and co-defendants Sifa Lee and Cheng Sun as they traveled to Majestic Dragon on Route 1, where owner Shui Keung “Tony” Woo, 62, of Quincy, was staying overnight.

Lawyers for the three had argued that because they didn’t know the machine could track their movements, and because investigators didn’t obtain a warrant, the evidence should not be used at their trial, expected later this year.

Judge David Lowy disagreed, pointing to a February Supreme Judicial Court decision finding that warrants are not required for a relatively short period of surveillance that would essentially be the same type of information that could be gathered by visual surveillance, such as an officer following someone.

Even if that decision had held that a warrant was required, “the defendants had no objectively reasonable expectation of privacy in the cab during their travels from Ipswich to Connecticut and back,” Lowy wrote in a decision issued Friday.

Prosecutor Kristen Buxton had compared the taxicab to a plane, where passengers expect that someone is keeping track of the location at all times. She also argued that the GPS data was being collected by a private business, not a government entity, so there was no violation of the Fourth Amendment, which prohibits unreasonable searches and seizures, or its equivalent in the state Declaration of Rights.

Lawyers Lawrence McGuire and Frank Santisi, representing Lee and Lin, suggested that police investigating the murder needed a warrant, which would have required a judge to find probable cause, in order to access the GPS data. Instead, investigators subpoenaed Creative Mobile Technologies.

The defense attorneys had asked for a full hearing on the question, where they would have had a chance to question investigators and other witnesses. Buxton had argued against that, and the judge, after a protracted series of discussions with the attorneys, agreed, saying that the affidavits submitted by the defense, as well as an affidavit by State Police Lt. Norman Zuk, who oversaw the investigation, were enough for him to make a determination.

Lin, 31, Lee, 37 and Sun, 48, are scheduled to stand trial next month, but that is expected to be delayed because there are other issues to address prior to trial, including a challenge to Lin’s arrest at the Canadian border.

The GPS data is important to the case because after police identified the cab, through an employee at a nearby business, they still needed to determine who was inside it. After determining that the cab traveled to the Foxwoods and Mohegan Sun casinos, investigators were able to obtain surveillance video and other information that helped them identify suspects.

Editor's note: On May 16, this story was edited to reflect the correct name of the credit card reader machine company, Creative Mobile Technologies.

©2014 The Salem News (Beverly, Mass.)