Using last month's assassination of two New York police officers as an example of the danger to law enforcement, Los Angeles Police Chief Charlie Beck urged Google CEO Larry Page, owner of the popular traffic app Waze, to disable a feature that shows the locations of police.
In a letter dated Dec. 30, Beck said he fears further harm to police after he said Ismaaiyl Brinsley used the Waze app to track law enforcement before killing Rafael Ramos and Wenjian Liu.
"I am concerned about the safety of law enforcement officers and the community, and the potential for your Waze product to be misused by those with criminal intent," Beck wrote. "I look forward to opening a dialogue with you as to how Google can prevent the future misuse of the Waze app to track law enforcement officers, thereby avoiding any future deaths or injury."
Waze, which Google purchased for $966 million in 2013, is a combination of GPS navigation and social networking.
Fifty million users in 200 countries turn to the free service for real-time traffic guidance and warnings about nearby congestion, car crashes, speed traps or traffic cameras, construction zones, potholes, stalled vehicles or unsafe weather conditions.
Waze users mark police presence on maps without much distinction other than "visible'' or "hidden.'' Users see a police icon, but it's not immediately clear whether police are there for a speed trap, a sobriety check or a lunch break.
The police generally are operating in public spaces.
A Waze spokeswoman, Julie Mossler, said the company thinks deeply about safety and security.
She said Waze works with the New York Police Department and others around the world by sharing information.
Google declined to comment.
"These relationships keep citizens safe, promote faster emergency response and help alleviate traffic congestion,'' Mossler said.
Beck joins a number of U.S. law enforcement officials expressing concern about the app.
But CHP Deputy Chief Chris O'Quinn said the app might encourage motorists to comply, slow down and drive safer.
The Associated Press contributed to this story.