NEW YORK — Five Columbia University students sold LSD-spiked candy and a full menu of other drugs at three fraternity houses and other residences on the Ivy League campus, and at least one student said the drug money was helping him pay for school, authorities said Tuesday.

The students were arrested at the school at dawn on Tuesday. They were to be arraigned in Manhattan on multiple drug-dealing charges.

Authorities called it one of the largest drug takedowns on a New York City college campus in recent memory. There was no immediate response to a phone message left with Columbia.

The arrest culminated a five-month investigation – dubbed “Operation Ivy League” – that relied on a youthful undercover officer posing as a drug middleman for another college outside the city. Special Narcotics Prosecutor Bridget G. Brennan said the officer made 31 purchases of LSD, marijuana, cocaine, Ecstasy and other drugs.

Authorities said most of the arrested students’ customers were other students and friends buying smaller amounts for recreational use. The liquid LSD was sold in Altoids and SweeTarts.