Mays apologized to the families involved.
"No pictures should have been sent out, let alone been taken," he said.
Mays and Richmond were tried before Lipps, a visiting judge, without a jury. The trial moved quickly -- and through the weekend -- to accommodate the judge's schedule.
Ohio Attorney General Mike DeWine said more charges in the case could be forthcoming.
After the convictions, DeWine said he is asking the Jefferson County Common Pleas Court to convene a grand jury on April 15. DeWine said that while calling a grand jury does not mean indictments will be returned or charges filed, "this community needs assurance that no stone has been left unturned in our search for the truth."
He said there were 16 people who had refused to talk to investigators.
He called the case a tragedy made even worse because the victim was revictimized through social media.
Back-to-school parties turned ugly
Mays and Richmond were accused of raping the girl during a series of end-of-summer parties in August 2012.
According to prosecutors, each of them penetrated the victim's vagina with his fingers, an act that constitutes rape under Ohio law if it is not consensual.
Attorneys for the two boys had said they were not guilty.
CNN's policy is not to identify alleged victims of sexual assault. CNN is not naming the minors who have testified but is identifying Mays and Richmond, whose names have been used by court officials, their attorneys and in multiple media accounts.
At the heart of the case was the question of whether the victim was too drunk on the night of August 11 and the early morning of August 12 to understand what was happening to her and to consent.
The victim testified Saturday that she remembered little about the night because she was drunk.
During closing statements on Saturday, attorneys for the two boys argued the state failed to prove beyond a reasonable doubt that their clients raped the girl, calling into question the victim's credibility.
They also questioned whether an avalanche of cell pictures and videos and social media posts available in the days after the rape, as well as national media coverage ahead of the trial, tainted testimony.
But prosecutors told the judge there is no question the girl was "substantially impaired."
"The things that made her an imperfect witness -- that she doesn't remember a lot -- made her in every sense of the word a perfect victim," prosecutor Marianne Hemmeter said.
Victim says she remembers little from the night in question
The girl testified Saturday that she remembered drinking at the first big party of the night and then holding Mays' hand as she left with him, Richmond and others.