MESQUITE, Texas – Mesquite police have released disturbing new details about a sexual assault that occurred on the campus of Horn High School involving a non-student male.

According to an arrest warrant, the victim’s mother warned police before the attack that the suspect had been harassing her daughter and threatening to show up at her school.

The victim’s mother even went to the school to personally notify the police there.

Hours later, police said the suspect, identified as 19-year-old Synnaiz Elijah, had carried out his threat.

He could bypass security at Horn High School on Tuesday afternoon, persuading another student to let him in through a locked exterior door.

He then found his ex-girlfriend in the hallway. The affidavit says he slapped her across the face, pulled out a kitchen knife and threatened to stab her.

The report says the teenager, fearing for her life, went into a bathroom stall with Ilie where he allegedly choked her and sexually assaulted her. He even hacked her Chromebook at school before running away.

“After the incident, it is our understanding that the victim went to the office and notified staff of what happened,” said Mesquite Police Officer Michael Kelly.

A teacher also saw Ilie in the hallway after the attack and approached him. Police said that’s when he ran off campus.

He was arrested Tuesday night at his home in Seagoville and is now charged with aggravated battery on a child.

The affidavit says security cameras at the school confirmed everything that happened up until the moment the suspect and the victim went into the bathroom, where there are no cameras.

A retired FBI special agent told FOX 4 that even the best security plans aren’t fool proof.

“If somebody goes and lets somebody in or opens a path for that person to have access without going through the proper steps, then it’s all wasted because then there’s an opportunity for somebody to take advantage of it,” Kenneth Gray said. , a lecturer in criminal justice at the University of New Haven.

In a letter to parents, the Mesquite Independent School District said the student who let Elijah into the building would be disciplined.

Some parents expressed concern about how long it went unnoticed and the district’s decision to wait until the next day to notify parents of what happened.

They will have a chance to voice their concerns at a Mesquite ISD school board meeting Thursday night.