Ohio Attorney General Mike DeWine, whose office is investigating and prosecuting the case, declined Friday on "Starting Point" to say whether anyone else could be charged in the case. But, he said, investigators are continuing to follow leads.
On Thursday, the police chief who initially investigated the case, before the Jefferson County prosecutor asked state officials to step in, said he doesn't expect much additional evidence to surface in the case.
"You can come up with conspiracy theories and everything, but for prosecutors to take a case to trial, you have to have substantial evidence, you have to have evidence that can be presented. And in this case, I don't believe there is much more," Steubenville Chief William McCafferty said.
He said he believes his town, and his force, have been portrayed unfairly.
"I think they have made our community look like something that its not. It's a very good community," he said. "Nobody condones rape, nobody condones lawlessness."
But McCafferty also said he's puzzled why no one intervened in the alleged assaults.
"Why didn't somebody stop it?" he said. "You simply don't do that. ... It's not done."
Authorities charged Richmond and Mays on August 27, the same day Jefferson County's prosecuting attorney asked DeWine's office to take over the case.
In addition to the rape and "nudity-oriented material" charges, the teens also were originally charged with kidnapping. A juvenile court judge dismissed that charge in October, according to McCafferty and Nemann, Mays' attorney.
"My client asserts his innocence, and he looks forward to his day in court," Nemann said.
Nemann also said that prosecutors gave letters to three teens who testified at the early hearing, telling them they wouldn't be prosecuted if they testified about what they'd done. Attorney General DeWine previously told CNN that prosecutors offered no deals. It was not immediately clear whether Nemann and DeWine differed on the existence of such letters, or on their definitions of "deal."
Local authorities asked the state to take over to show that "everything that can be done in this case is being done," county prosecutor Jane Hanlin told CNN affiliate WTOV at the time.
"And if that means eliciting the help of these people from the attorney general's office, then that's what we want to do in this case," she said.
In addition, the FBI has offered "some technical assistance" in the investigation, said FBI spokesman Todd Lindgren in Cincinnati. He did not go into detail. Offering such assistance is routine, he said.
The case has been complicated by a lack of physical evidence -- the family did not report the alleged assaults until August 14. It also apparently hinges largely on witness statements, social media images and messages posted after the incident and possibly some information gleaned from cell phones seized by police. The family gathered many of the materials and delivered them to police on a portable computer drive, McCafferty told CNN.
Police have heard of a video showing the alleged attack, McCafferty said. But authorities don't have it or know whether it even exists, he said.
Police did seize several cell phones and iPads during the investigation, and "there was evidence on some of the phones," McCafferty said without elaborating.
The New York Times reported that a cell phone photo from that night shows the girl naked on a floor.
A special unit with the attorney general's office is examining the materials, McCafferty said. DeWine's office has declined to comment on evidence in the case.
Text messages posted to social networking sites that night, later retrieved and published by a crime blogger, seemed to brag about the incident, calling the girl "sloppy," making references to rape and suggesting that she had been urinated on, according to crime blogger Alexandria Goddard. CNN has not established whether that is true.