A U.S. congressman fired an aide because she was allegedly corresponding with Scott Peterson, a California man convicted of killing his pregnant wife in a prominent trial, while she was on the job.

The Louisiana Republican fired Theresa Mares in mid-August, said spokesman Adam Terry. Mares had worked for Alexander since he first took office in 2003 and was a caseworker in the congressman's Alexandria office in central Louisiana.

Terry said Alexander learned of Mares' letters to Peterson from a National Enquirer reporter. In August, the tabloid reported that Mares sent at least 18 letters to Peterson professing her love for the convicted killer.

Terry said Alexander decided to fire Mares because she was "using government resources to personally communicate with Scott Peterson."

"Ms. Mares' actions have been embarrassing to our office and demonstrate that her views are politically incompatible with those of the congressman," Terry said.

Mares could not be reached for comment; her number was not listed.

Peterson was sentenced to death in 2004 for killing his wife and their unborn son. Their bodies were found on the shore of San Francisco Bay months after her December 2002 disappearance. Peterson is on death row in San Quentin Prison in California.