There’s a new Facebook scam that everyone needs to watch out for. The ruse begins with cyber-thieves hijacking a Facebook account and ends with outright theft.

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

The message requests funds be wired to the stranded friend via Western Union. The ruse has worked in several well-publicized cases.

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

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

But Scherrman’s case isn’t an isolated one. I recently received an e-mail from a friend in Texas whose Facebook was hijacked in the same fashion. My friend found she couldn’t log into her account and then heard from friends asking about her predicament in London.

Facebook says it’s working with law enforcement to try and track down the culprits in these cases, and the social networking site administrators claim they have systems to detect suspicious behavior tied to compromised accounts.

But the best bet is to change your account password frequently and let the site owners know immediately if access to your account is blocked.

And it might not hurt to keep a separate list of all your friends and their e-mail addresses so you can warn them if anything suspicious goes on with your account.