An investigation is under way into where a powerful date rape drug may have come from amid reports by two University of Montana students that they were sexually assaulted by men — aided by the drug.

Some medical experts say recipes for drugs similar to Rohypnol may include household ingredients. That could make efforts to locate a supplier for drugs allegedly used in crimes potentially very difficult. First Step Resource Center registered nurse Cat Otway says that even over-the-counter medicines mixed with alcohol can be used as date-rape drugs.

The University of Montana has already enlisted an outside investigator to pursue allegations lodged earlier this month that two female students had been attacked.

Story From Associated Press