The Supreme Court on Wednesday ruled that the collection of GPS data by police without a warrant during an investigation into a man suspected of a string of thefts in the Kansai region was illegal.
The 15 members of the court’s Grand Bench ruled that collecting data using a GPS invaded privacy and therefore constituted a mandatory investigation, which required a warrant.
But the court also raised doubts about whether an existing verification warrant could be used, underscoring that new legislation would be necessary to cover such GPS use.
Endorsing lower court rulings, it sentenced the defendant, 45-year-old Katsushi Iwakiri, who had admitted to thefts between February 2012 and September 2013, to five years and six months in prison.
The legality of warrantless surveillance had been a point of contention during Iwakiri’s trial. During their investigation, the police installed 16 GPS tracking devices to vehicles belonging to Iwakiri as well as other suspects over a period of about six months without a warrant.
Investigators tracked the location of one of the devices more than 1,200 times.
The defense counsel claimed that this violated Iwakiri’s privacy, while calling for new legislation on warrants as the current system did not cover the collection of GPS data.
Prosecutors argued that the use of tracking devices was legitimate because the surveillance method fell under the same category as a police stakeout or tailing, which do not require warrants.
They said during the court hearing that even if GPS surveillance would be considered a mandatory investigation — which would require a warrant — the current system covered the practice without the need for additional legislation.
Lower courts have been divided about the legality of the GPS use.
The Osaka District Court found in June 2015 that the police collection of GPS data without a warrant was illegal and struck out related evidence.
The Osaka High Court in March 2016 said it found no serious law violation in the investigation. But it did not rule on whether warrants are required for GPS data collection.
The Japan Federation of Bar Associations said in January that conditions and procedures for the use of GPS in investigations should be set.
The National Police Agency issued a notice in 2006 on GPS use, stating it could be used in investigating serial thefts, organized criminal activity involving drug and firearms and kidnappings — all crimes which require a swift response and where tailing subjects would be difficult.
The agency encouraged prefectural police nationwide in a notice last September to first obtain a verification warrant in some cases.
In January, it was revealed Chiba Prefectural Police last year obtained a warrant before putting a GPS device on a vehicle — a first in Japan — but presented the warrant to the subject only after the investigation.
Iwakiri had not argued against his sentence from the first trial. He said prior to the Supreme Court ruling that he was ready to serve his time.
“I have fought (to the top court) because I just could not accept the way they investigated. I want the top court to correct the wrong,” he said.