Four students in Elyria, Ohio were arrested and charged with aggravated menacing, making terrorist threats, or carrying a concealed weapon after a series of "hit lists" were found at Franklin Elementary School and Eastern Heights Middle School.

The students, all of whom are currently unidentified, have since been taken to Lorain County Juvenile Detention Home, Elyria Police Captain Christopher Costantino told Fox News on Friday.

The first incident occurred on April 19 when a 14-year-old female student at Eastern Heights Middle School was involved in a physical fight with another student. Afterward, the school’s principal found a “hit list” inside her backpack. The teenager was arrested after she made threats to “shoot up the school,” Costantino said, though he noted that teen did not have a gun at the time she was taken into custody.

The student claimed she had written the list for someone else, Costantino said. However, police have not yet determined if her statement is true or not.

Days later, on April 24, a 10-year-old girl at Franklin Elementary School was arrested after a knife was found in her backpack. She also allegedly co-wrote a hit list with a 10-year-old boy at the school who was also arrested.

The list, which school officials had been made aware of and later found in the trash, detailed all the people the students reportedly wanted to “stab to death,” police records said, according to FOX8.

A student informed a teacher that the 10-year-old girl was “telling other students that she had a knife, hit list and intended to stab people,” Costantino said.

Later on, the students told police that the names on the list were people who “were not nice to them.”

The same day, another hit list was found, again at Eastern Heights Middle School. A 12-year-old boy was arrested after a teacher reportedly overheard another student ask him to “show me the list of people that you want to kill.”

The 12-year-old boy and the 10-year-old boy who were arrested are brothers, the police captain said.

As of now, police do not think the lists are connected, Costantino said, though he called the timing of the incidents somewhat unusual.

“This is the first time this has ever happened,” he said.

Moving forward, “it’s a two-fold process -- the criminal part of it and the school’s disciplinary process,” he said, adding that the children will likely be suspended or even expelled.

“We want to find the underlying cause of why they are so angry and why they are expressing their anger like this,” he said. Costantino said that the middle school boy who was arrested told police that making a list was “his way of venting his anger.”

Costantino said both schools did a “great job” handling the incidents, praising the officials for their quick actions.

“Matters of student and school safety are of the utmost urgency, and as a school administration and law enforcement team we will continue a no-tolerance approach to threats and violence, while continuing to delve into the issue of student behaviors and student responses to emotional and social issues they may be experiencing at school and at home,” Amy Higgins, communications and marketing director for the Elyria school district told Fox News in a statement. “It is our greatest priority to keep our students and staff safe and to provide a secure environment, so students feel protected and are learning to their full potential.”

“We wish to commend our students and staff in these situations for quickly reporting information, and our administrative team and our Elyria Police Department partners for their calm, swift and deliberate handling of the situations for the safety of all,” the statement continued.

“Our hope is that these kids get the help they need,” Costantino said, adding that he's hopeful the students “understand the severity of this and the hurt it has caused.”