A Baltimore murder-for-hire suspect, whose case the American Civil Liberties Union (ACLU) joined as an amicus last year, has now taken a plea deal and will receive a sentence of four years and nine months in prison.

The ACLU had supported Robert Harrison’s earlier motion that the government be required to disclose information about how it used a stingray, or cell-site simulator, without a warrant, and therefore the court should suppress evidence gathered as a result of its use.

Earlier this week, Ars reported on the fact that the FBI believes it does not need a warrant when using a stingray in public.

Prior to the Harrison case, the ACLU had not been involved in a stingray case since Daniel David Rigmaiden , an Arizona man convicted of tax fraud who took a plea deal and was released on time served in April 2014.

While stingrays do target specific phones, they also sweep up cell data of innocent people nearby who have no idea that such collection is taking place. Authorities have been notoriously tight-lipped about precisely how such devices are acquired and implemented.

Former federal magistrate judge Brian Owsley (now a law professor at Indiana Tech) has been unsuccessful in his efforts to unseal similar orders despite intimate familiarity with the legal system. And in November 2014, local prosecutors in an unrelated Baltimore robbery case even dropped key evidence that stemmed from stingray use rather than allow a detective to fully disclose how the device was used.

A trial had been set for February 2, 2015.

"This case is now over, but we continue to work with defense attorneys in Maryland and elsewhere to identify cases where the government surreptitiously tracked phones using stingrays and to obtain court review of unconstitutional surveillance," Nathan Wessler, the ACLU attorney in the case, told Ars.

"Despite the government’s efforts to shroud its activities in secrecy, we know that stingray use is widespread, and we are confident that there will be more cases challenging warrantless stingray use in the future."