HARTFORD, Conn. » Wesleyan University’s president on Monday urged students to come forward with knowledge of anybody distributing drugs on campus following a rash of hospitalizations among people who took a party drug known as Molly.

A total of 12 people — 10 Wesleyan students and two visitors — received medical attention over the weekend, including some who attended a rave music show Saturday night.

"If you are aware of people distributing these substances, please let someone know before more people are hurt," President Michael Roth wrote in a letter to campus.

The school became aware of the problem early Sunday after several students showed up seeking treatment at a Middlesex Hospital near campus, university spokeswoman Lauren Rubenstein said. Two students listed in critical condition Sunday were airlifted for treatment in Hartford, 20 miles north of the campus in Middletown. Two others were taken by ambulance to Hartford Hospital in serious condition.

Four others were expected to be released from Middlesex on Monday, Roth said.

Molly is a term used to describe a refined form of Ecstasy, a synthetic drug also known as MDMA. It can drive up body temperature and cause liver, kidney or cardiovascular failure.

Dr. Mark Neavyn, chief of toxicology at Hartford Hospital, said users who believe they are taking Molly are often receiving different kinds of designer drugs, with ranges of purity and potency making the health risks unpredictable. He said testing is underway to confirm what drugs the Wesleyan patients took.

"When we see these people in the emergency department and they claim to have taken Molly, we don’t pay attention to that word anymore. It’s so commonly not MDMA, we just start from square one and say it’s some sort of drug abuse," Neavyn said.

It was not the first such episode this year at the private school of nearly 3,000 students.

Wesleyan health officials said in a campus-wide email on Sept. 16 that students had been hospitalized the previous two weekends after taking Molly. Students were urged to visit the school’s health center if they had questions or concerns.

In his Monday letter to campus, Roth included a telephone number students can call to make a confidential report.

"These drugs can be altered in ways that make them all the more toxic. Take a stand to protect your fellow students," he wrote.

Some of the students who required medical attention attended a rave at the school’s Eclectic Society social house on campus, Rubenstein said. The show featured disc jockeys from New York who go by the name Swim Team. They did not immediately return an email seeking comment.

"Some of the students were there but not all of them, and there is not necessarily a connection there," Rubenstein said. "They are really looking all over campus."

The hospitals and the school declined to provide updated patient conditions Monday, citing privacy concerns.

Middletown police Chief William McKenna said his department was pursing information about a "bad batch" of the drug.

"Our first and foremost goal is to obtain information on the batch of Molly that was distributed to the students on the campus," McKenna said. "This information is critical in ensuring the recovery of those students affected."

Associated Press writer Michael Melia contributed to this report.