House report urges clearer guidance on cellphone technology

House lawmakers say Congress should set clearer guidelines for law enforcement's use of cellphone tracking technology.

A House committee report released Monday examines the use of cell-site simulators, including devices known as stingrays, by federal, state and local enforcement agencies.

A cell-site simulator works by tricking phones into believing it's a cell tower, collecting basic data from phones in a particular targeted area. Police use it to determine a suspect's location.

The technology has been broadly adopted by police departments, and the House Oversight report says the Justice Department spent more than $71 million between fiscal years 2010 and 2014 to acquire devices. But the technology has raised Fourth Amendment concerns among privacy advocates for its ability to collect cellphone information about innocent bystanders as well as criminal suspects.