Former Oak Hills physical education teacher indicted on new child exploitation charges

CINCINNATI — Mark Altherr, a former Oak Hills School District fitness instructor accused of possessing and distributing child pornography, now faces more than a dozen new federal charges related to his alleged exploitation of children, court documents show.

Altherr was arraigned in federal court on the new charges on Wednesday.

Altherr initially faced one federal charge of distribution of child pornography and one federal charge of possession of child pornography.

Now the 45-year-old also faces more serious charges: 16 new charges of child sexual exploitation.

Court documents show the charges relate to Altherr’s illegal and explicit interactions with a victim who was between the ages of 5 and 6 when the crimes were allegedly committed.

According to court documents, Altherr is alleged to have produced child pornography depicting the victim “engaging in and assisting another person in performing sexually explicit acts” on at least 16 occasions between May 30, 2023, and June 20, 2024.

The documents further state that child pornography investigators found images of “a minor who was pre-pubescent and a minor who was under the age of 12.”

From there, Altherr distributed the explicit content to others online, the documents said. Altherr faces one charge for each video or image he took of the child, which was found on a USB drive, the court documents said.

Federal court documents initially alleged that Altherr distributed sexually explicit material depicting children on a website from December 2023 through July 2024. The new indictment reveals that investigators determined that Altherr created and distributed child pornography prior to that time, as early as May 2023.

The website Altherr used, which launched around 2019, specifically describes itself as “a child pornography community,” court documents state.

The FBI’s investigation found that Altherr was an active member of that website and posted files, some of which contained child pornography, according to court documents. The FBI determined that Altherr had been using the site since 2021 and that he had posted at least 262 messages to the site during that time — some of which were posted as recently as six months ago, according to court documents.

After learning that Altherr was a teacher at Delshire Elementary in Delhi Township, FBI agents felt it was “imperative” to find Altherr. On July 26, they went to his home in Cincinnati but found he was not there, court documents said. A ping of his cellphone showed investigators he was in a public location in Columbus, Ohio, the FBI said.

An FBI agent was dispatched to that location in Columbus, where they found Altherr’s vehicle, court documents state.

“On July 26, 2024 at approximately 7:54 p.m., the officer observed an individual matching Altherr’s description get into a vehicle with a minor female,” the criminal complaint filed against Altherr states.

Agents watched as Altherr drove herself and the child to a Columbus-area hotel, the document said. That same day, agents viewed images Altherr had posted to the website, including images of child sexual abuse. Based on that information, FBI agents said they believed the child with Altherr “was in imminent danger when she entered the hotel with Altherr,” the criminal complaint said.

As a result, officers executed a probable cause arrest on Altherr. After he was arrested, officers entered his hotel room and discovered a young girl, completely naked, the document said.

Later that same evening, FBI agents executed a search warrant at Altherr’s Cincinnati home. During the search, both images and videos of child sexual abuse, some as young as 3 or 4 years old, were found on electronics in Altherr’s home.

Altherr is currently being held in the Butler County Jail on the orders of federal officials. He must remain in custody until his trial.

The FBI encourages anyone who believes they or someone they know may have been a victim of Altherr’s actions to complete a short online form.

“Don’t make them feel embarrassed, give them the space to come forward and talk to us,” said U.S. Attorney for the Southern District of Ohio Kenneth Parker. “We urge everyone to come forward so we can hold him to the highest level of accountability.”

Altherr accepted his position at Delshire Elementary School in the Oak Hills Local Schools District in 2019. He was employed as a fitness teacher at the elementary school until his arrest. Before coming to Cincinnati, Altherr taught at various schools in Colorado for nearly two decades.

His personnel files, which WCPO requested after his arrest, do not show any prior complaints or disciplinary action. However, documents in the file show that the FBI could not rule out that Altherr’s students were victims of his actions.

“From the FBI’s perspective, we are just beginning our investigation and at this point we cannot say with certainty that no students were harmed and that no activities occurred at the school,” the FBI spokesperson said. “We need time to review all of the material related to child sexual abuse (CSAM).”

Earlier in August, the OHLSD Board of Education voted to move forward with Altherr’s termination process. Before that, on July 30, the district sent a letter to parents and staff notifying them of allegations against Altherr and that he had been placed on unpaid administrative leave.