"It's scary, and you need to be careful. I've gone through my friends list, and tightened all of my security settings."
When police officer Justin Tereny, 22, was killed in the line of duty after just six months on the job, the town of Tecumseh, Oklahoma was devastated.
A year later, as the tight knit community mourned, a fake profile with Officer Tereny's photo appeared on Facebook. Chief of Police J.R. Kidney was puzzled -- and his grief turned into outrage.
"I couldn't believe that someone would stoop that low, Kidney recalled in an interview with NBC News. "They had created a Facebook profile page stating that he was married, that he was from Iowa, and that he was currently working at the Kansas City, Kansas Police Department."
Kidney says he contacted Facebook to remove the fake profile, but never heard back after multiple attempts.
"Our response from Facebook has been zero," said Chief Kidney. "I haven't heard anything from Facebook, they've never contacted us at all."
The world's largest social network is struggling in a battle against fake profiles as digital thieves steal identities, endanger children and hurt small businesses. The problem has become so big that Facebook said that it has disabled over 1.3 billion fake profiles just in the past year.
NBC News examined dozens of cases where identity thieves stole identities to create fake Facebook profiles, using stolen identities.
Earlier this month, former Atlanta City Councilman Alex Wan found his photo plastered across multiple fake profiles that were used to attract women. Wan told NBC News that he had over 100 friends report the page as fake, before it was eventually taken down a day later.
In another case, Brandi Beckham says a woman stole photos of her 1-year-old twins from her Facebook page, claiming their parents had died and she had adopted them.
"It's scary, and you need to be careful," Beckham said. "I've gone through my friends list, and tightened all of my security settings."
Facebook says they removed the fake profile with Officer Tereney's photo in June. However, the police chief says that it took more than a month, and multiple requests, before Facebook took action.
In a statement to NBC News, Facebook said, "This was a mistake and we are very sorry that we did not remove this profile sooner. We thank the law enforcement officials who reached out about this issue. We removed the impersonating profile on June 19."
"Our Community Standards do not allow people to misrepresent themselves or impersonate others. We are focused on authentic connections and know we need to do better in situations like this one. We have made several recent improvements to combat impersonation, including automation to detect scams, and improved reporting abilities," said Facebook.
Facebook also pointed to advancements in machine learning that can detect impostors and fraudulent activity.
Some industry experts say that a dependence on machine learning is not enough.
"The problem is they've built a platform that is just well beyond their ability to monitor it," said Kara Swisher, executive editor of Recode.
"It's so easy to manipulate this platform because it's so open and has such easy tools that it's hard to imagine they'll be able to catch all the bad players -- and there are a lot of bad players on this platform."