This experiment was conducted in both Seattle and Milwaukee, but it was Seattle's data that proved of interest. The team was specifically looking for towers that didn't behave normally, such as appearing and disappearing or changing location. Of 1,400 mapped cell towers in Seattle, three specific ones were of interest: one at SeaTac airport, one at the Seattle office of the US Customs and Immigration Service and one in a West Seattle neighborhood. While the third may have been a false positive, the researchers believe their data strongly hints at stingray usage at the first two locations.

There's no proof of whether stingrays are actually operating in these locations or not -- after all, they wouldn't be secret surveillance devices if they were easy to detect. And the Seattle team acknowledges that they probably missed quite few stingray uses, as detecting them depended on one of their cars driving by right as a stingray was activated. But this is an encouraging first step for those who are concerned about the law enforcement's use of these devices to collect data and eavesdrop on conversations. These researchers may have made it easier to track stingray use in the future, and in a relatively cost-effective way.