CTIA is warning consumers of an e-mail scam that uses its logo.

The e-mail uses CTIA's branding to lend authenticity to a phony offer for a free cell phone. Further details of the fraudulent offer were not available, and the number listed in the e-mail was out of service.

"CTIA takes the illegal use of our name and logo seriously," CTIA General Counsel Michael Altschul said in a statement. "We are investigating this situation, but warn consumers that CTIA has nothing to do with this message. If you receive an email with our name and logo saying you 'won a cellphone,' we advise you to not respond."

The e-mails may differ, but tell people that they have won a free cell phone through a CTIA promotion. An example of the inauthentic offer provided by CTIA reads: "We came up with this promo this year since 1984 when the association started we have never had a good out [sic] sales before, so in our own way to say thank you to mobile phone users we held a promo draw, we got your number from the international network command by tracking our cell phone chips."

The association first became aware of the fake e-mails after being alerted by a consumer. It is not clear how widespread the spam messages are.