Two 16-year-old Bartlett High School students face felony charges after authorities say they hacked into the school's computer system.
One of the male students was charged with aggravated computer tampering and the other was charged with computer fraud, police said Tuesday.
Their names are not being released because they are juveniles.
Elgin Area District U-46 officials first notified police Dec. 11.
District officials said at the time the students hacked into a U-46 online portal and changed student attendance records. The duo also hacked into at least one U-46 staff member's email account, according to the district.
The students learned how to get around the district's firewall filter restrictions and improperly uploaded a software program onto U-46 computers that tracks keystrokes, enabling hackers to crack passwords to log into accounts, district officials said.
All staffers in the high schools were told to reset their account passwords. The district also removed compromised computers.
Bartlett police say the duo did not know two St. Charles East High School students behind another computer security breach in December.
In that case, the students, also juveniles, were expelled after officials said they shut down the St. Charles Unit District 303 computer network, keeping teachers from using online grading and other programs for about a month.
In U-46, there were no service disruptions.
The teens were taken to DuPage County Juvenile Court Jan. 13, police said, and then released from custody to their parents. Police would not comment Tuesday on the specifics of the investigation. District officials also did not immediately respond to email and phone messages.