SILOAM SPRINGS, Ark. — Police arrested a student at a Christian college in Arkansas, alleging he told officers he had been building small bombs and that he posted a note in a dormitory common room saying “the maniacal side” of his brain was a “fun little guy” who wanted to inflict mass casualties on society.

Timothy Constantin, a 20-year-old John Brown University student from Gainesville, Florida, was arrested Tuesday and was being held pending a bond hearing Thursday morning, said the local prosecutor’s office, which didn’t know if he had an attorney.

In an affidavit, detective Ron Coble said Constantin had built small bombs with PVC pipe and black powder collected from fireworks and ammunition. The student had written that one side of his brain “genuinely hates and actively wants to murder ever (sic) single human I come across as well as those I’ve never seen in my life.”

Police began investigating after other students said Constantin was suicidal. One student told Coble that Constantin wanted to kill himself to prevent himself from committing a terrorist attack over the upcoming winter break.

Officers said they found guns and ammunition in Constantin’s dorm room, including an AK-47 rifle and a Keltech 9mm carbine gun. Constantin told police in interviews that the firearms were for protection and that if he were to do a mass killing, he would use explosives. Police found no explosives in his room. Coble’s affidavit said Constantin told another officer he had previously made explosives.

The university released a statement saying it was increasing the number of armed guards on campus and reviewing training procedures after the arrest.

“While the student indicated thoughts of harm to himself and potentially to others, to the best of our knowledge there was not a specific plan to carry out any type of campus attack nor was there a specific person targeted,” the statement said. “If Campus Safety or the Siloam Springs Police determined there was immediate risk to the campus, we would have alerted campus through our crisis alert system.”

An arrest warrant directed officers to hold Constantin on a complaint of engaging in criminal acts involving explosives, a felony punishable by up to 10 years in prison.