Attorneys for a 19-year-old accused of sexually assaulting several girls at his former high school say there is a 'treasure trove' of evidence proving the girls lied about the abuse, but the lawyers want further access to Facebook accounts to prove it.

Tyler Kost, who appeared in court on Monday, was arrested last May for sexual crimes against 13 girls between 13 and 17 years old, most of whom were former classmates at Poston Butte High School.

The Pinal County Attorney's Office says Kost faces 30 charges in three indictments ranging from sexual abuse to child molestation.

Pictured: Tyler Kost has been in jail for over a year since a group of teenage girls accused him of sexual misdeeds

Accused: Attorneys for the 19-year-old accused of sexually assaulting several girls at his former high school say there is a 'treasure trove' of evidence proving the girls lied about the abuse

Kost stared straight ahead throughout most of the proceedings, his expression waffling between consternation and sedation. He looked older than in his booking photo with pale skin and close cropped brown hair.

Kost's defense said new evidence taken from Facebook and Instagram proves the women lied about sexual abuse.

'Over a year ago Mr. Kost was publicly accused of being a serial rapist. What we know now is that there was a group of girls who conspired against Tyler to put him in jail. They succeeded in that, and Tyler has now been in jail for over a year based on those lies,' Kost attorney Christine Whalin told KSAZ.

The prosecution handed over 98,000 pages of social media records from several of the alleged victims, but Defense Attorney Michael Alarid said he needs the communications of at least 8 other people to determine how far the plot spreads.

The court documents reveal a group Facebook chat where three of the accusers and three witnesses made plans to 'teach a lesson' to Kost and referred to the movie 'John Tucker Must Die,' where ex-girlfriends take revenge on a former boyfriend.

'Tyler needs to be taught a lesson,' ran one interaction, reports KSAZ, as well as 'We should sacrifice him to Satan.'

And another exchange read:

'I'm down,'...'I already know this is going to be so much fun!'

In court: The prosecution handed over 98,000 pages of social media records from several of the alleged victims, but Defense Attorney Michael Alarid said he needs the communications of at least 8 other people to determine how far the plot spreads

The exchange happened weeks before the women accused Kost of sexual assault.

Facebook's privacy policy prevents the defense from gaining access to the other records, Alarid said. Only law enforcement can request the information from Facebook, he said.

'Quite frankly the fact that the state is refusing to get any additional social media records is concerning. It's shocking. Based on what we've uncovered so far they should be dismissing several charges. Instead they are digging their heels in and they are refusing to give us anything additional,' Alarid said.

Prosecutor Shawn Jensvold said the records are not in the state's control and can't be turned over to the defense. Further, he said, the defense has not demonstrated a substantial need for the information.

Taking cues? The court documents reveal a group Facebook chat where three of the accusers and three witnesses made plans to 'teach a lesson' to Kost and referred to the movie 'John Tucker Must Die,' where ex-girlfriends take revenge on a former boyfriend. The film stars Jesse Metcalfe and Ashanti

Jensvold said that the Facebook conversation only shows that three of the victims might be involved in a revenge plot, but not the other 10 victims.

'It's not the state's job to go on a fishing expedition for the defense, which is very clear within the case law,' he said.

Kost was arrested after the Pinal County Sherriff's Office received a tip accusing him of sexual assault against five victims. He was booked on two counts of sexual assault and two counts of sexual misconduct with a minor. Detectives later identified eight other girls who said they were sexually abused by Kost.

A spokesman for the sheriff's office said that in at least one case Kost threatened, harassed and told a victim to kill herself. In another, a victim said she became pregnant when she was raped after a Poston Butte homecoming dance.

Judge Kevin White set the next hearing for May 4 at the Pinal County Superior Court.