College officials in the northeast are greeting returning students with a warning after multiple deaths due to overdoses of Molly, a powder form of MDMA, the active ingredient in Ecstasy.

At the Electric Zoo festival in New York City, University of New Hampshire student Olivia Rotondo collapsed into a seizure on Saturday and later died after allegedly taking six hits of Molly. Syracuse University graduate Jeffrey Russ, 23, also died as a result of drug use following the concert.

The two New York deaths follow that of Brittany Flannigan, a 19-year-old Plymouth State University student who died from an overdose of Molly at a Zedd concert at the House of Blues in Boston on Aug. 28. Two others in their 20s also overdosed at the concert but survived. Another three men in their 20s were sickened by overdoses of Molly at a techno-rock concert at the Bank of America pavilion on Saturday in Boston.

At the deceased students’ alma maters, officials are working to warn students about the dangers of MDMA.

“This is serious. Two New Hampshire college students have died in the last week,” Mark Rubinstein, UNH’s vice president for student and academic services, said in a campuswide email.

Jim Hundreiser, Plymouth State’s vice president for enrollment and student affairs, told NECN that residence hall advisers will be watching for risky behavior.

“The other thing we’re doing,” Hundreiser said, “is we’ve created a care form, which is an opportunity for anyone in the campus community to alert us if they’re concerned about a student.”