The California Attorney General's office said Friday that it is investigating a prescription drug ring linked to late actor Corey Haim.

According to the Attorney General, an unauthorized prescription in Haim's name was found during an investigation into fraudulent prescription pads ordered by a San Diego vendor. Authorities have not released when the prescription in Haim's name was found.

The ring operated by ordering prescription drug pads from authorized sources, but using stolen doctor identities, according to the Attorney General's office. The pads were either sold to prescription drug users, or to people who would then fill the prescription and sell them on the underground market, the Attorney General's office claims, saying that the doctors whose identities are stolen are usually not aware of it.

There have been 4,500 to 5,000 fraudulent prescriptions in Southern California linked to the ring under investigation, the Attorney General's office reports.