Here’s how it works: Hackers break into a Facebook account, change the password and send messages to the user’s “friends” announcing that the account holder is stranded in London.

The message requests funds be wired to the stranded friend via Western Union. Would you respond to a request for money sent by someone in an emergency who chose Facebook of all methods to contact you? Apparently, plenty of people would.

For example, a Missouri woman was tricked into wiring about $4,000 to someone in England after receiving a help messages from a friend on Facebook.

Jayne Scherrman of Cape Girardeau wired the money through Western Union after receiving what she believed were several requests for help from her friend, police said.

Scherrman’s case isn’t an isolated one. Facebook has received reports of similar scams and says it’s working with law enforcement to try and track down the culprits. The site’s administrators claim they have systems to detect suspicious behavior tied to compromised accounts.

The best bet for prevention is to change passwords frequently and let the site owners know immediately if access is blocked.