There are growing concerns that Google's  Waze application poses a danger to police because of its ability to track their locations. The tech giant is now under pressure by top cops to turn off the traffic app's police-tracking function. The Waze app, which operates like a free GPS navigation tool, allows users to tag the locations of parked police vehicles, accidents, congestion, traffic cameras, potholes and more, so that other drivers using Waze are warned as they approach the same location. There are growing concerns that Google's Waze application poses a danger to police because of its ability to track their locations. This image taken from the  app on an iPhone, in Washington, shows police at the scene on a map on the app . Waze, which Google acquired Waze in 2013 for a reported $1.1 billion has 50million users in 200 countries, a number which is growing. Ismaaiyl Brinsley, 28, killed two NYPD police officers. Before the killing he was known to have used the app to monitor the movements of police . However, several police officers say the app is being used to stalk and plan attacks on law enforcement. Ismaaiyl Brinsley, 28, killed police officer Wenjian Liu and his partner Rafael Ramos in December while they sat in their squad car. Before the killing he was known to have used the app to monitor the movements of police officers and posted screenshots of the app on Instagram. He wrote of his admiration for Waze, according to screenshots taken by Breitbart, which he was using to track two officers in Staten Island, New York. The post was said to be made in early December. He used the same account to announce his intentions to gun down the two officers in Brooklyn, styling it as a revenge attack for the deaths of Eric Garner and Michael Brown. It has since been deleted. Investigators do not believe he used Waze to ambush the officers, because police say Brinsley tossed his cellphone far from where he shot the officers. A Waze spokesperson said in a statement to MailOnline: 'Waze was not used in the attack on the two New York City police in Brooklyn in December, nor has it ever been used to attack law enforcement officer. 'It is not possible to “stalk” or follow a police officer by using Waze.' 'There are many ways the police feature supports officer safety and the overall goals of law enforcement. Namely, police partners have told Waze they want to be seen, often publishing 'speed trap' locations ahead of time in the US. Cop tracker: Screenshots emerged of Brinsley posting to Instagram about his use of the Waze app - on which users post updates . 'The US national Move Over law requires drivers to move one lane away from emergency or law enforcement vehicles when stopped; our alerts work to keep police safer as drivers are notified before they round a turn or pass one unexpectedly while driving highway speeds.' After typing in their destination address, users just drive with the app open on their phone to passively contribute traffic and other road data, but they can also take a more active role by sharing road reports on accidents, police traps, or any other hazards along the way, helping to give other users in the area a 'heads-up' about what's to come. In addition to the local communities of drivers using the app, Waze is also home to an active community of online map editors who ensure that the data in their areas is as up-to-date as possible . But the Los Angeles police chief insists it does endanger lives and wrote a letter to the tech company's CEO. According to the document police chief Charlie Beck sent to Google CEO Larry Page on December 30, people are using the 'unwitting' Waze community as 'their lookouts for the location of police officers.' '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 to endanger police officers and the community,' the letter said. Google (which acquired Waze in 2013 for a reported $1.1 billion) claims the app 'is all about contributing to the 'common good' out there on the road,' the risks far outweigh the potential benefits, reports CNN. Sheriff Mike Brown of Bedford County, Virginia, said states might pass laws to prevent people from revealing the locations of parked police cruisers. Privacy advocates, however, said First Amendment protections will stand in the way. 'Waze represents person-to person information in the public square,' said Nuala O'Connor, head of the Center for Democracy and Technology, a Washington civil liberties group, who said she uses the software. 'And that's long been a U.S. right under the Constitution.' There are no known connections between any violent attack on police and the Waze software.
Google is being put under pressure to turn off Waze, following fears it might put officers' lives at risk . Waze helps drivers avoid congestion, accidents and traffic cameras . App, owned by Google, also warns drivers when police are nearby .