O’FALLON, Ill. (AP) — Police in O’Fallon, Illinois are investigating a complaint that marijuana-laced brownies were given out during a high school’s summer band camp as a prank.

Authorities say at least three students at O’Fallon Township High School are suspected in the Aug. 1 prank, though no charges have been filed.

Police say the brownies secretly tainted with marijuana were given to 23 students at the camp, but none of them experienced ill effects.

Police say they learned of the prank after one suspected student told another about it, and that student reported it to a school official.

Copyright Associated Press