The American Civil Liberties Union has filed a brief supporting a challenge to the use of a cellphone tracking device in a federal case in Maryland, arguing that the technology raises "serious Fourth Amendment concerns" and that authorities misled a judge in obtaining a court order.
The case involves a murder-for-hire sting conducted by Baltimore police and the FBI this year, according to court records. Police gave a cellphone to Derrick Smith so he could communicate with an undercover officer, and later used a device known as a stingray to locate the phone.
The device, which was developed for the military, mimics a cellphone tower to force all phones in range to connect to it. Civil liberties advocates say it exposes the information of bystanders.
The stingray helped police pinpoint the phone inside the home of Robert Harrison, who along with Smith is now facing murder-for-hire charges.
The disclosure by authorities that they had used a stingray was a rare admission regarding a technology that police across the country have sought to keep secret, The Baltimore Sun reported this week.
Harrison's attorney, C. Justin Brown, is fighting to suppress the phone evidence on the grounds that its use amounted to a search that was not clearly authorized by a court order.
The government, in its response to Brown's filing, said it could not discuss the technology in detail but that the court order police obtained was appropriate.
In its supporting brief, the ACLU adds to Brown's arguments, saying the device's ability to locate phones inside homes raises questions about whether it is subject to sufficient court oversight.
"No search warrant … would permit the police to search the homes of every house in a neighborhood," the ACLU atorneys wrote. "Yet, with the stingray, the police can do just that, searching every home, vehicle, purse and pocket in a given area without anyone ever learning that their devices were searched by the police."
The organization cites two recent cases, reported by The Baltimore Sun, in which police said they were able to locate a phone inside a home or moving vehicle. Prosecutors in two other Baltimore cases withdrew evidence recently after police told a city judge they couldn't discuss the device.
"In Baltimore," the ACLU wrote, "police are invoking a secret nondisclosure agreement with the federal government to justify affirmative concealment of information about stingray use from judges and defense counsel."
The government said the court order obtained by authorities, called a pen register, covers the technology because it refers to cellular tracking device and GPS location information.
But the ACLU argues that the state's statute for such pen register orders "makes no provision for, or even mention of, a 'cellular tracking device' " and is commonly understood to only include the "trapping" of call log information.
"In addition, there is absolutely no indication in the application or the order that the authorization will subject potentially unlimited numbers of innocent third parties to dragnet surveillance, none of whom will ever receive notice that their phones were tracked and that the search will intrude into constitutionally protected spaces," the ACLU wrote.
The government says it can't discuss stingrays because it would tip off criminals. The ACLU says information about the technology is already in the public domain.
Arguments are scheduled for January.