Officials won't say who's in custody, reports "Early Show" national correspondent Hattie Kauffman.
But California Attorney General Jerry Brown told CBS News, "We have a prescription that was fraudulently obtained for Vicadin in the name of Corey Haim, OK? And an individual connected with that operation has now been arrested. That's what we know."
Haim had acknowledged his addiction to powerful painkillers before he collapsed in his mother's apartment March 10.
Just after Haim died, "The Early Show" spoke to his friend and co-star, Corey Feldman. "Yes, there were prescription medications," Feldman said. "Yes, he was still weaning himself off of those prescription medications. And yes, he was still enduring an ongoing battle with drugs."
Investigators say Haim got thousands of pills from dozens of doctors, according to Kauffman.
"The addiction takes over," Brown remarked, "and the patient wants to keep going. They doctor shop, and when they can't get enough doctors to prescribe, then they go the illegal route."
That route involves fraudulent prescription pads, and forged doctor's signatures, Kauffman explains.
The question now, Kauffman points out, is how Haim got hold of so much Vicadin, Valium and other drugs as recently as a week before his death.
CBS News legal analyst Lisa Bloom says she thinks, "What's happened was with this first arrest, they're hoping to bring someone in to talk to law enforcement. Now they have a fire lit under this person because an arrest has been made. Probably, they're trying to get more information from this person against higher-ups in the drug ring so they can make further arrests. But … the drug ring has been called massive and I think this is just the first arrest."
Bloom says California authorities are trying to send a message about prescription drug fraud and abuse, taking it "very seriously. … Jerry Brown in this case has brought charges against one person. In the Anna Nicole (Smith) case, charges have been brought against two doctors and Anna Nicole's former boyfriend. (The doctor in the Michael Jackson case also faces counts).
"I think the message is getting out there and getting out there very clearly that, whether you are involved in prescription drug fraud as an identity theft individual, as a doctor who is negligently prescribing or overprescribing or as an individual who's doctor-shopping, the authorities will come after you."
What can be done to stop "doctor shopping"?
Dr. David Sack, CEO of Promises Treatment Centers, told co-anchor Maggie Rodriguez, "Doctors take their patients on faith, they take their word. And, so if someone's going from doctor-to-doctor, they're not going to know it. I think that it starts by asking every patient if they have a history of alcohol problems or other drug problems, because those patients are much more likely to abuse narcotics if they are prescribed. And I think the second thing is that patients frequently will start to call doctors for early refills and that's another indication that there may be something wrong."
Bloom says a national prescription drugs registry has been mentioned. "I can go to a doctor today, I could go to another doctor tomorrow and a third doctor the day after that, and try to get the same prescription medication if I'm an addict," Bloom notes. "And the only way to really prevent that is a national registry so doctors could check in and see what this patient has from other doctors. That wouldn't prohibit people from getting the drugs fraudulently, but it would be a help.
"The problem on the other side of that are privacy concerns. Patients are rightly concerned about having all of their drug medication out there in some kind of national registry, so that's the tension on that issue."