ST. LOUIS — Defense attorneys are questioning the impact of local police using U.S. Secret Service cellphone tracking technology in 2014 to investigate a case.

Attorney Diane Dragan argues that some of the charges and all of the evidence stemming from her client’s arrest should be tossed out of court because the cellphone tracking performed by the technology is illegal.

The St. Louis Post-Dispatch ( ) reports that lawyers say the legal mechanism police cite to justify the use of the technology is inadequate because federal prosecutors say the use of the system is akin to a formal search, which requires a search warrant.

St. Louis police are now getting warrants before using the tech, but attorneys say the concession could affect older cases.

Megan Beesley, a public defender in St. Louis who’s handled cases involving the technology, said area defendants aren’t told when the technology has been used in their cases.

Last week, a U.S. Secret Service agent described in court how the technology is used. He said that officers request information from a cellphone carrier through a special website and within hours, police receive the information, including the cellphone tower that is being used and an approximate location of the phone.

Once officers are at the approximate location, the tracking device is activated and all phones in the area are compared to the one that authorities are looking for.

The agent said that no data from the phones is saved after the search is conducted.

Beesley and Dragan said they learned on Tuesday that the Secret Service maintains records of the searches that they perform.

Nathan Freed Wessler, an attorney with the American Civil Liberties Union’s Project on Speech, Privacy and Technology said the ACLU believes that police should exhaust all other options before using the tracking technology because of its invasiveness to the suspect and other cellphones in the area.

Information from: St. Louis Post-Dispatch,