Editor's note: Please note this story contains graphic language.
Steubenville, Ohio (CNN) -- A computer forensics expert testified Thursday about text messages to and from one of two Steubenville, Ohio, football players accused of raping a drunken teenage girl.
The testimony from Joann Gibb of the Ohio Bureau of Criminal Investigation came on the second day of a case that focuses heavily on texts, cell phone images and social media posts surrounding the alleged sexual abuse of the 16-year-old girl in August 2012.
Two Steubenville high school football players -- Trent Mays, 17, and Ma'lik Richmond, 16 -- are accused of sexually assaulting the girl during a series of end-of-summer parties in August.
The teens are charged with rape. Mays also charged with illegal use of a minor in nudity-oriented material. Defense attorneys say the two are innocent.
According to prosecutors, Richmond and Mays each penetrated the victim's vagina with their fingers, an act that constitutes rape under Ohio law.
Prosecutors contend the text messages between Mays and his friends and classmates on August 12 detail a night of heavy drinking and the sexual abuse of the girl.
The defense questioned the validity of the messages, with Mays' attorney asking Gibb whether she could be absolutely sure the messages were from his client.
"I can't put a person behind a cell phone," she said.
Some of the messages were between Mays and the alleged victim.
In one message she asks what happened "last night."
"And don't lie about anything. I need to know the truth. People keep asking. Idk (I don't know) what to say," the message said, according to Gibb.
Mays responded that "nothing happened last night," telling her in the message she performed a sex act on him, Gibb testified.
CNN is not identifying the girl in line with its policy of not identifying the alleged victims of sexual assault. CNN is also not identifying minors who testify at the trial but is identifying Mays and Richmond, whose names have been used by court officials and their attorneys and in multiple media accounts.
Some of the messages from Mays, according to Gibb, say he had sex with the girl while in others he say the girl performed a sex act on him.
One message asked Mays: " Did u do it?"
He responded, according to Gibb: "No, lol. She could barely move."
Another message to Mays from still another friend asked "how dead is she?"
Mays responded, according to Gibb, "not at all, she's looking for her phone."
Still another graphic message from Mays to a friend appeared to detail his anger over being accused of rape.
"I'm pissed all I got was a hand job, though. I should have raped since everyone thinks I did," the message said, according to Gibb.
The testimony Thursday showed just how much of the case rests on the prosecution's stance that the alleged victim was too drunk to consent to sex.
'Stumbling and slurring'
One of the witnesses, a college freshman who described himself as a friend of Mays and Richmond's cousin, testified he saw the alleged victim "stumbling and slurring her words" at the first of a series of parties that night.
The next day, he testified he texted Mays from a friend's phone asking about the alleged rape and told him he could go to jail for that.
Mays responded, according to the witness, that the girl knew what she was doing.
The witness said he responded: "No, she don't."
Asked why he said that, the witness said "because I saw how drunk she was at the party."
On cross-examination, the witness admitted to Richmond's attorney, Walter Madison, that he was angry by what he heard happened to the alleged victim because he considered her a friend.
A police captain also testified Thursday about finding two photos of a nude girl on a cell phone belonging to Mays.
Consent vs. non-consent
The case will hinge not on consent but rather on whether Mays and Richmond knew that the girl was too impaired to know what was happening the night of the alleged attacks, prosecutor Marianne Hemmeter said in opening statements Wednesday.
Six witnesses for the prosecution testified Wednesday, saying the alleged victim appeared to be drunk: stumbling, swaying and throwing up.
One witness, a 17-year-old girl who went to a party with the alleged victim, said she and the girl shared a half a bottle of vodka, which they each poured into a flavored crushed ice drink.
The alleged victim also had a beer and seemed to get drunk very quickly, the witness said.
The party broke up about 12:30 a.m., and the girl left with Mays and Richmond, according to the witness, who said she pleaded with her not go. The witness said she didn't see the girl again until the next day, when she picked her up at another home.
She described the girl as a "mess," wearing her stained shirt inside-out.
On cross-examination, Richmond's attorney, Madison, asked the witness whether her view of what had happened that night had been framed by the tweets and social media posts she had seen about the victim and whether what she had seen in those messages made her angry.
She said it had.
Another witness, a 17-year-old friend of Richmond's, said on cross-examination that while the girl appeared drunk, he did not believe she was unaware of what she was doing.
The boy also told Mays' attorney, Brian Duncan, that he hadn't seen the girl drinking and had not witnessed Mays involved in any sexual contact with the girl.
The trial, which is likely to stretch into the weekend, is moving quickly to accommodate the schedule of visiting Judge Thomas Lipps, who is presiding over the trial without a jury. A verdict is expected by Sunday.
The case has cast an unwelcome spotlight on Steubenville, a small, down-on-its-luck town along the banks of the Ohio River.
Critics have accused community leaders of trying to paper over rampant misconduct by players of the highly regarded Steubenville High School football team and have suggested that other students took part in the assaults or failed to do enough stop them.
The case has attracted the attention of bloggers and even the loosely organized hacking group Anonymous, which have questioned everything from the behavior of the football team to the integrity of the investigation.
CNN's Poppy Harlow and Brian Vitagliano reproted from Steubenville, Ohio, and Chelsea J. Carter wrote and reported from Atlanta.