Stevenson High School is in the midst of an ongoing probe into student misconduct that involves the use, possession and intent to distribute drugs, an official confirmed Tuesday.
The primary drug at the center of the investigation is marijuana, but it may expand to include others.
Stevenson High School District 125, in conjunction with the Lincolnshire Police Department, launched the investigation in earnest in late December.
Earlier that fall, a student had been under investigation for "something that blossomed into something much larger," said Jim Conrey, the district's spokesman, declining to discuss the nature of that probe.
"The investigation began with an incident involving one student which then turned out to have roots and tentacles into something farther reaching, but the extent of that we don't know because we're still doing the investigation," Conrey said.
Police Chief Peter Kinsey could not be reached for comment Tuesday night.
Conrey confirmed there have been no arrests thus far, but declined to give details on the number of students who face disciplinary action, pointing to student privacy policies.
He also would not release an exact number of students targeted in the probe, but said student claims that 100 to 200 students were either expelled or suspended during the investigation are "wildly exaggerated.".
District board member Terry Moons declined to comment, citing the ongoing investigation.
The prestigious high school of roughly 4,000 students is situated in the tony community of Lincolnshire and routinely recognized as one of the nation's top high schools.
And the ongoing drug investigation will do nothing to tarnish that sterling reputation, Conrey said.
"We're still an excellent school and every high school has a certain percentage of students that choose to go down wrong paths," Conrey said, adding that it's the biggest drug probe to hit the school in the 18 years he's been there. "We're not different from any other school. Unfortunately, this is a societal problem that has manifested itself in a school setting."