The University of Mississippi on Thursday named two undergrads, from Colorado and Georgia, as the students found dead earlier this week in cases that sparked renewed concerns about the drug kratom.

Aidan Hamilton, an 18-year-old freshman from Englewood, Colorado, and Robert Strang, a 20-year-old junior from Atlanta, died this week, Ole Miss said.

Both students were found on Monday, one on campus and the other in the city of Oxford, authorities have said. Packaged kratom was discovered during each of these separate death investigations, but no definitive link has been made between the drug and these deaths, officials said.

Kratom is an herb with opioid-like effects sometimes sold at gas stations or online. It has gained popularity in the U.S. as an unapproved treatment for pain, anxiety and drug dependence. Kratom can either be stimulating or sedating, depending on the dosage taken, according to the Drug Enforcement Administration.

Shawnboda Mead, the vice chancellor for student affairs, urged the campus community to reserve any judgement until law enforcement finishes its probe.

“We know there is heightened media attention and that you may be eager for answers. We also recognize that inaccurate information is being shared by individuals who do not have access to the facts,” Mead said in statement.

“We can all help by not repeating information that has not been officially confirmed and by avoiding public speculation about what happened or why, especially as the causes of the two deaths are still under investigation.”

Phi Delta Theta identified Strang as a member of its fraternity.

“Out of respect for Robert, his family, and those closest to him, the Fraternity has refrained from public comment until his name was publicly released,” Phi Delta Theta said in a statement on Thursday.

“The loss of two young lives is a profound tragedy,” the fraternity said. “Phi Delta Theta joins the University of Mississippi and the broader Ole Miss community in mourning Robert and Aidan Hamilton and extending our deepest sympathies to their families, friends, chapter brothers, classmates, and all those who knew and loved them.”