Substitute teacher, who allegedly raped 14-year-old student, found dead in his jail cell

ST. LOUIS (TND) — A substitute teacher who had been jailed after he allegedly raped a 14-year-old student has reportedly been found dead in his cell.

The cause of 30-year-old Brandon Holbrook's sudden death is apparently a mystery, according to local reports.

Authorities found Holbrook unresponsive in his jail cell on Monday, according to KMOX News, adding that the alleged rapist was then transported to and pronounced dead at the hospital.

Investigators reportedly say that there is no evidence of drug use or trauma and that an autopsy is set to be performed.

Holbrook had been charged with raping a female student from Bernard Middle School, where he was substitute teaching, KMOX News reported. He allegedly groomed the young teenage girl over social media and raped her on at least three separate occasions at her home.

The 30-year-old was reportedly facing six counts of second-degree statutory sodomy and three counts of second-degree statutory rape.

St. Louis County Police Sgt. Tracy Panus has also said that other victims have come forward with similar allegations against Holbrook, according to the St. Louis Post Dispatch.

According to local reports, Holbrook was found unresponsive while in an upright position, and did not respond when addressed.

This prompted jail staff to enter the cell to check on him and after they saw he was unresponsive they began CPR and administered Narcan, a drug that's used to save people suffering from drug overdoses.

A lawyer for Holbrook, Scott Rosenblum, told the St. Louis Post Dispatch that his client's death "seems very unusual."

I know for a fact he was not suicidal," Rosenblum reportedly said.

Holbrook is reportedly the third inmate to die at the St. Louis County Justice Center this year alone.

An autopsy will attempt to determine the 30-year-old's cause of death.