Attorney Joseph McCulloch said he has a client who was charged with possession of marijuana and questioned about the now-infamous party Phelps attended near the University of South Carolina campus in November. He said his client's roommate also was arrested.
McCulloch didn't name his client, who faces up to 30 days in jail and a $200 fine if convicted on the pending charge.
The Richland County Sheriff's Office would not comment on the lawyer's remarks.
"As soon as we're ready to release information on this case we will and we're still in the middle of this investigation," said Lt. Chris Cowan.
The lawyer representing the host of the party, who's also been arrested, told Early Show news anchor Russ Mitchell Thursday the case is all about celebrity.
"It just seems to me," Richard Harpootlian remarked to Mitchell, "(that), with all the crime we have, and the serious drug offenses occurring out there, this is a ridiculous waste of resources."
Columbia television station WIS-TV reported earlier this week that eight arrests had been made, but did not cite a source. McCulloch said college students and lawyers have told him that about eight arrests have been made.
After the photo was published Feb. 1, Sheriff Leon Lott said his office would investigate and possibly bring a charge against Phelps, though his spokesman has not specified what the offense might be.
Phelps, 23, and his team have not disputed the photo's accuracy. Phelps has issued a public apology, acknowledging "regrettable" behavior and "bad judgment" after the photo appeared.
McCulloch said his client and the roommate used to live at the house where the party that Phelps apparently attended took place, but they have since moved out of the city. Richland County deputies searched the alleged party home and then searched the roommates' new home in Irmo and made the arrests, he said.
He said his client was out of town when the swimmer visited the city and said he doubted that anything the client or his roommate - who has a different lawyer - told police would assist them in the case against Phelps.
"Our clients answered questions but I don't know that their information would be helpful to law enforcement," he said. "It seems to me that Richland County has a host of its own crime problems much more serious than a kid featured in a photograph with a bong in his hand."
Under South Carolina law, possession of one ounce or less of marijuana is a misdemeanor that carries a fine up to $200 and 30 days in jail for the first offense. Possession of drug paraphernalia is a $500 fine.