It follows their announcement last Friday that Haim's name was found on a fake prescription supplied by that drug ring.
"That investigation has uncovered thousands and thousands of prescriptions that are being used in Southern California to move drugs that would be legal if prescribed by a physician," said state Attorney General Jerry Brown. "But in this case they are being sold by a criminal syndicate."
On Tuesday, hundreds of family and friends said goodbye to the former teen star at a funeral in Canada.
Haim battled addiction for many years. He had been staying with his mother in an apartment in Universal City for about a year. His mother found his body and called 911.
She told the call dispatcher, "I am pressing, I am pressing, but he is not moving. He all of a sudden got out of bed and wanted to go to the bathroom and he fell on the floor. I put him on his bed and then that was it. His eyes went backwards."
A coroner's report shows that Haim had an enlarged heart and water in his lungs at the time of his death. Toxicology reports are still pending, but authorities say a drug overdose cannot be ruled out.
The attorney general says Haim had recently obtained massive amounts of legal drugs including, OxyContin and Vicodin from several doctors.
Authorities say the drug ring being investigated stole the identities of doctors to fill out fake prescriptions, and they believe Haim obtained drugs using those prescriptions.
"These dangerous substances are available by unscrupulous people who find a way to impersonate doctors to get these prescription pads," said Brown. "With that they get the fulfillment from the pharmacies and then they sell the drugs on the open market."
Haim died at 2:15 a.m. at Providence St. Joseph Medical Center in Burbank, on March 10, 2010. He was 38 years old.
The actor broke into the film industry in 1984 as a child actor. He starred in movies such as "Lucas" with Charlie Sheen, but his breakthrough role came with his 1987 film "Lost Boys."