A debate between privacy and protection is heating up again, and Facebook is front and center.

It's no secret the stuff you post publically online can be monitored, but your private chats, too? According to Reuters, the answer is yes.

Facebook's chief security officer admits Facebook users are being monitored for any suspected criminal activity, and it's not just the stuff you post on timelines.

Using software, the company says it's monitoring personal chats as well. Using smart software, Facebook scans those chats for certain phrases, exchanges of personal information and vulgar language.

If it sees something suspicious, it flags it, and only then would an actual person read it. At that point, a security team takes over, reads the chat and then contacts police if needed.

Facebook says the technology has a very low false-positive rate to protect its users' privacy, but as expected there has been backlash from users. Some feel their private conversations are being violated.

But the company points to one instance where the technology helped net an alleged sexual predator: The software red-flagged a man's chat with a 13-year-old girl in South Florida.

In the conversation, authorities said he was making plans to meet with her after school. It was tagged by Facebook and shipped to police, who arrested the man.

The FBI says it's on board with this technology and hopes more online sites use it.