Facebook keeps a list of people who are potential threats to its employees

Facebook keeps a list of hundreds of people, including users and ex-employees, who have made threats against the social media company and its employees, according to CNBC on Thursday. 

The company uses data from those people's Facebook accounts and sometimes tracks their location through the app when threats appear credible, CNBC reported. Some former employees who spoke to CNBC questioned the company's ethics, but others said that the tech giant is keeping its employees safe.

A Facebook spokesman confirmed that it does keep a list of people who might a pose a threat to the company and its employees, but said it's "standard in terms of corporate security." He declined to say how many people are on this list. 

The company also defended its actions in a statement to CNBC.

"Our physical security team exists to keep Facebook employees safe," a Facebook spokesman said in a statement to CNBC. "They use industry-standard measures to assess and address credible threats of violence against our employees and our company, and refer these threats to law enforcement when necessary. We have strict processes designed to protect people's privacy and adhere to all data privacy laws and Facebook's terms of service. Any suggestion our onsite physical security team has overstepped is absolutely false." 

Facebook has been faced criticism for not doing enough to protect the privacy of its 2.3 billion users. But the social media company and other tech giants have also had to deal with real threats against their employees.

In December, police evacuated buildings at Facebook's Menlo Park headquarters following an anonymous bomb threat. The San Mateo bomb squad swept the buildings but did not find suspicious packages or devices. In April, a suspected female shooter opened fire on employees at YouTube's San Bruno headquarters, wounding three workers before taking her own life.

Facebook created a "be on lookout" list in 2008 and it's updated every week, according to former employees who spoke to CNBC.

When a person is added to the list, security professionals receive a report that includes their name, photo, location and why they were added, according to the news outlet.

One Facebook users discovered he was on the list after he tried to enter Facebook's campus for a lunch with a friend who worked at the company. Security guards showed up when he tried to register as a guest and he reportedly was on the list because of messages he sent to Facebook CEO and co-founder Mark Zuckerberg. The user was removed from the list after his friend complained to the company. 

Sometimes, Facebook will also add former employees to the list if they've made threats against the company, CNBC reported. 

Other tech companies also keep a list, but Facebook uses the social network to find threats and can track people's location through their own service. That has included Facebook users and even its own interns if they go missing. 

A former employee told CNBC that the social network only tracks a person's location when a threat appears credible. 

First published at 12:50 p.m.

Update, 1:35 p.m.: Includes more background. 

Update, 1:49 p.m.: Includes statement from Facebook.

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