SAN DIEGO -- Several Marines have been arrested on charges of working with a group that stole ballistic vests and other gear from Camp Pendleton and sold it on the Internet, authorities said Wednesday.

Authorities have arrested nine people so far, including several Pendleton-based Marines, the Department of Homeland Security said in a press release. Additional arrests were expected.

The nine include Erika Jardine, who was sentenced Wednesday to six months in prison by Judge Michael Baylson in U.S. District Court in Pennsylvania. The Vista resident and civilian pleaded guilty in November to one count of exporting arms without a license and one count of selling stolen U.S. government property.

Jardine has cooperated extensively with the government and "made great strides in attempting to right her wrongs," prosecutors wrote in a sentencing memorandum.

An ongoing investigation at Camp Pendelton by the Naval Criminal Investigative Service has identified 12 Marines and several civilians as suspects, Homeland Security said.

U.S. Immigration and Customs Enforcement agents launched an investigation of Jardine in June 2004 and discovered that she was selling illegal gear in Internet auctions on eBay, Homeland Security said. Agents who posed as arms merchants based outside the United States allegedly bought 18 ballistic vests from her.

Homeland Security said the investigation has resulted in the recovery of items worth more than $63,100, including 17 vests, 104 lightweight ceramic plates used in the vests, seven Kevlar helmets, 74 M-16 magazines, two gas masks and 100,766 Iraqi dinars.