The two students were questioned, but no one was in custody Saturday, Police Sgt. Brian Skornia told the Milwaukee Journal Sentinel.
The investigation is ongoing, authorities said.
School officials at Wauwatosa East High School said that although they took the bomb plot threat seriously, the plans did not advance to the point where students were in danger.
Police reports indicate that the plot involved researching online how to make a bomb and the chemical agent napalm, as well as how to make gunpowder.
The students discussed placing bombs underneath a lunchroom table and in the school's stairwells, the police report states.
"He chose about six tables that he wanted the bomb to hit, one of which was the table of someone who used to bully him. He did not want to kill the people that sat at these tables, but only wanted them to suffer. As such, he wanted the bomb to be of a type that would only blow off their legs," the report states.
The students described their plot as an intellectual exercise, the police report states.