People v. Smith, 2017 IL. App. (1st) 14-1814-U (Ill. App. 2017)
Police investigating a string of robberies of food delivery drivers accused Smith of robbing and shooting a pizza delivery driver. Detectives found Smith through his cell phone: Using the phone number provided to order the pizza, officers obtained a court order to “go up on a pen register, specifically trap and trace devices on telephone number 773-981-5292.”
Officers used the signals from his cell phone to locate Smith as he walked along the sidewalk. They grabbed Smith, took him to the ground and searched him. They found his cell phone in his pants pocket. Smith asked the court to suppress the surveillance evidence derived from the phone, claiming that he was arrested without warrant or probable cause.
More to the point, the court cited well-established evidentiary rules for establishing foundation to testify about mechanical or electronic surveillance devices.
At the suppression hearing, a detective testified that they used a “pen register” to trap and trace the numbers dialed on Smith’s phone. However, the defense argued that the detective described technology that was more consistent with use of a StingRay device. Rather than merely trapping and tracing numbers, a StingRay is capable of precisely locating a targeted cell phone within a specified area. A StingRay simulates a cell site, forcing cell phones in range to send their signals to the cell-site simulator. Once the cell phones in the area send their signals to the StingRay, it captures information that can be used to identify the cell phone serial number and to locate the cell phone in real time.
The detective who located Smith’s cell phone signal couldn’t explain how a trap-and-trace device such as a pen register allowed him to pinpoint the phone’s precise location. The appellate court said that the detective’s testimony didn’t seem consistent with the operation of pen registers: “The record reveals that the officers’ testimony about the surveillance technology was sparse, vague, obfuscating and at times incoherent.”
Though many courts have discussed the Fourth Amendment implications of using a StingRay device (see “No Need to Tell Judge about StingRay Use” and “Warrant Required for StingRay Cell-Site Simulator Device”), that’s not the focus of this case. The court considered whether the prosecution established a sufficient foundation for any evidence of surveillance technology it used to track Smith’s phone. The court held that the detective’s testimony failed to show any scientific or technical knowledge about the device, whether it was a pen register as claimed or not. Moreover, there was no evidence that the device—whatever it was—worked properly when it was used to locate Smith’s phone.
The court was highly critical, noting that the witnesses “painfully—indeed fatally—failed to provide any critical details” about the technology used. More to the point, the court cited well-established evidentiary rules for establishing foundation to testify about mechanical or electronic surveillance devices. The takeaway: Officers must educate prosecutors about whatever technology is used and be prepared to adequately explain it to the court.