T-Mobile quietly reported a sharp rise in police demands for cell tower data

T-Mobile has reported a small decline in the number of government data requests it receives, according to its latest transparency report, quietly published this week.

The third-largest cell giant in the U.S. reported 459,989 requests during 2018, down by a little over 1% on the year earlier. That includes an overall drop in subpoenas, court orders and pen registers and trap and trace devices used to record the incoming and outgoing callers; however, the number of search warrants issued went up by 27% and wiretaps increased by almost 3%.

The company rejected 85,201 requests, an increase of 7% on the year prior.

But the number of requests for historical call detail records and cell site information, which can be used to infer a subscriber’s location, has risen significantly.

For 2018, the company received 70,224 demands for historical call data, up by more than 9% on the year earlier.

Historical cell site location data allows law enforcement to understand which cell towers carried a call, text message or data, and therefore a subscriber’s historical real-time location at any given particular time. Last year the U.S. Supreme Court ruled that this data was protected and required a warrant before a company is forced to turn it over. The so-called “Carpenter” decision was expected to result in a fall in the number of requests made because the bar to obtaining the records is far higher.

T-Mobile did not immediately respond to a request asking what caused the increase.

Call records requests by police. (2017 above, 2018 below). Source: T-Mobile.

The cell giant also reported that the number of tower dumps went up from 4,855 requests in 2017 to 6,184 requests in 2018, an increase of 27%.

Tower dumps are particularly controversial because these include information for all subscribers whose calls, messages and data went through a cell tower at any given time. That can include the data of hundreds or thousands of innocent subscribers at any time.

Although T-Mobile says it requires a court order or a search warrant, the Carpenter decision does not affect police accessing data obtained from tower dumps.

T-Mobile currently has 81.3 million customers as of its last earnings call. The company is currently in the middle of a merger with Sprint for $26.5 billion. The Justice Department is reviewing the bid, but several states are looking to block the deal entirely.