The Office of Special Investigations at Hill Air Force Base detained Cesar Olveda on Friday afternoon and Layton detectives took him to the city police station for questioning, according to a probable cause statement.

Police were alerted earlier Friday to an Instagram post that said, “I’m gonna bomb attack St. Joseph’s Catholic School in Kennewick, Washington.” The post invited police and the FBI to “come and get me” and gave a Layton street address.

Instagram gave police the IP address associated with the post and told investigators that the post came from that street address, the arrest affidavit said.

Lt. Travis Lyman, Layton Police Department spokesperson, said Monday that family members told investigators that Olveda has been diagnosed with schizophrenia and autism. “He’s apparently done this several other times, starting in 2014,” all of the threats targeting the Kennewick school, Lyman said.

The arrest affidavit said police found a journal in Olveda’s room allegedly detailing plans to blow up the school.

Police said Olveda declined to speak to investigators. He was booked into the Davis County Jail, where he remained held Monday on suspicion of second-degree felony terroristic threats. Formal charges had not been filed by midday Monday.

Lyman said Olveda did not attend the school and allegedly fixed upon it as a target “for an unknown reason.” He said he was not aware of any evidence that Olveda had done anything to carry out the threats.

“We implemented our safety protocols promptly and are grateful to the police for promptly investigating,” the school principal, Perry Kelly, said by email. “We hope Mr. Olveda gets the help it appears he needs, to prevent this from happening again. It is stressful for the children, parents and staff.”