An 18-year-old high school student in Arizona has been arrested on suspicion of sexually assaulting at least 10 and as many as 18 high school girls, and authorities continued to plead Friday for any additional victims to come forward.

Tyler Kost was being held without bond after being arrested late Thursday. In court documents and statements, the Pinal County Sheriff’s department has described Kost as a “serial rapist” who impregnated a 15-year-old and allegedly threatened to shoot in the head each girl who rejected his sexual advances.

His three-plus years of suspected escapades appeared to be well-known around school, and some of the assaults allegedly involved girls whom Kost was dating.

Girls and their family members accused Kost of using texting, Facebook and other messaging apps, including Snapchat and Kik, to befriend girls, invite them on dates and then kiss them before growing rougher. The assaults are suspected to have taken place in his San Tan Valley bedroom, girls’ bedrooms and in public spaces, such as parks and parking lots.


“He was, from all of the accounts of the victims, somebody who was highly manipulative, very charismatic and charming,” Sheriff Paul Babeau said at a press conference Friday.

Kost’s attorney, Joey Hamby, declined to comment. But in court Friday, he unsuccessfully sought a gag order to prevent the sheriff from making what he said were damaging statements about Kost before the case was even brought before a judge.

Florence Unified School District officials told reporters that Kost had been taking classes online since February after he reported that girls at the school were bullying him.

The sheriff’s investigation began in late March when a male tipster reported several of the suspected assaults after hearing from one of the victims. Deputies spent April tracking down victim after victim, coming up with 13 by Monday and then an additional five after the case against Kost was publicly announced.


Last October at the age of 17, authorities said, Kost is suspected of raping a 15-year-old girl in a park after the Poston Butte High School homecoming dance. The girl told police she ran home crying when a passing car startled Kost and allowed her to escape. When she learned she was pregnant, police said, she confronted Kost. He threatened to smear her reputation if she underwent an abortion, she told investigators.

All of the victims’ names are redacted in court documents provided by the sheriff’s department.

In November 2012, a girl was on a first date with Kost at his family’s home and told police that the teen raped her despite her physical and verbal demands that he stop. He briefly stopped when a younger sibling walked in on them, according to the court documents.

Kost then carried the girl downstairs and raped her again, the girl told police. She said she was manipulated and threatened into dating him for 10 months.


A similar assault took place in Kost’s family home last spring, a different victim said.

Another girl said Kost drove her deep into the desert and refused to take her back unless she had sex with him, according to the court file.

In one situation this past February, Kost is accused of chasing a girl around a parking lot. She eventually reached her car, but couldn’t roll up the manual window before Kost allegedly molested her, according to court documents.

Two rape victims were so traumatized that they left the state, the sheriff said. One of them required hospitalization following a suicide attempt, deputies said.


Kost was initially arrested Monday, but posted $10,000 bond later that day. Deputies said they worked around the clock to process new tips to rearrest him and and then asked a judge to hold him without bond.

The suspected sexual assaults appear to date to at least spring 2011 and continued through last month, according to the sheriff’s account. The victims range in age from 13 to 17 years old.

So far, Kost faces seven counts of sexual conduct with a minor under the age of 15, seven counts of sexual assault, seven counts of sexual conduct with a minor, three counts of sexual abuse of someone under the age of 15 and one count of sexual abuse.

The counts stem from 10 of the 18 cases and carry a statutory minimum of life in prison without the possibility of parole.


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