Police were guarding the doors of Chesterfield High School as students arrived for their first day since a classmate was accused of plotting to bomb the building.
Authorities say bomb-sniffing dogs checked the halls and classrooms. Metal detectors were borrowed from a courthouse and police met students at the doors.
Police Chief Randall Lear says about 17 law officers are trying to keep things as normal as possible at the school by keeping unauthorized people away from the building. He says the officers also are on hand to give the community some confidence.
School officials say attendance is down about 40% Monday.
Authorities say an 18-year-old Ryan Schallenberger was arrested Saturday after his parents called police when 10 pounds of ammonium nitrate - an oxidizing agent in explosives - was delivered to their home in Chesterfield. Police say it was purchased from eBay.
The same chemical was used in the 1995 Oklahoma City bombing.
Schallenberger is currently charged with possession of bomb making materials with intent of mass destruction and making a bomb threat.
Police Chief Randall Lear says the teen planned to make several bombs and had all the supplies needed to kill dozens, depending on where the devices were placed and whether they included shrapnel.
"There is no completed devices, but there is enough ingredients to where it would be a matter of just minutes to put something together," said Lear.
Lear says a journal Schallenberger kept for more than a year had detailed plans including maps of the school, but did not name targets of an attack.
Police say Schallenberger also had an audio tape explaining why he wanted to bomb his school, and wanted it to be played after he died.
The 18-year-old Schallenberger was assigned an attorney during a brief hearing Monday. He didn't say anything, but appeared agitated at the cameras awaiting him when he entered in an orange jumpsuit. He was handcuffed and his ankles were shackled.
His attorney, William Spencer, did not immediately return a call seeking comment.
We spoke with the principal of Chesterfield High School, and people who say they are in class with Schallenberger.
"I'm debating whether or not to go to school," said student John Huntley on Sunday.
Students and teachers at Chesterfield High School were on edge.
"Metal detection devices, they will walk through tomorrow and a lot of law enforcement to make sure we don't have any problems," said Chesterfield Principal Scott Radkin on Sunday.
Radkin assured parents and students to not worry about the plot, but they have made phone calls to make sure everyone is informed.
"They send it out to all the homes in the attendance area. It's not just students but everybody gets a call," said Radkin.
A student who says she has three classes with Ryan says she still wasn't sure if she feels comfortable attending class.
"He's nice. He's not somebody you would expect that would do anything. He's not somebody that gets into trouble," she told WIS News 10. "Not in Chesterfield. Not in the small town."
And in a scary coincidence, Sunday marked the 9th anniversary of another school attack.
In 1999, Eric Harris and Dylan Klebold, students at Columbine High School in Littleton, Colorado, went on a shooting rampage.
They killed 12 other students and a teacher before committing suicide.
The teens took a year to plan the attack, and illegally obtained the firearms from adults.
At least two of those adults were subsequently sentenced to prison.
In addition to the guns, the pair had constructed nearly 100 bombs and exploded many of them during the morning of terror.
Schallenberger was being held at the Chesterfield County Detention Center on Monday afternoon.
The principal of Chesterfield High School says Schallenberger had not caused any serious problems before his arrest, but a prosecutor says he will ask that Schallenberger undergo a mental evaluation when the teen appears in court Tuesday for a bail hearing.