PRINCETON – Authorities arrested a Princeton University student Tuesday when he went to pick up a package containing 7 grams of ecstasy at a campus mailroom.

In mid-December, agents with the U.S. Department of Homeland Security and U.S. Customs and Border Protection intercepted the package from overseas addressed to Julian Edgren, authorities said.

The university's public safety department was contacted and the Mercer County Narcotics Task Force was brought on to help.

Task force officers were assigned as surveillance inside and outside Frist Campus Center in an attempt to arrest any individual who retrieved the package. On Tuesday afternoon, officers arrested Edgren, 20, after he signed for the package and two others, authorities said.

During searches of one of the other packages and Edgren's dorm room in Edwards Hall, police seized 40 grams of psilocybin, commonly known as mushrooms, 31 marijuana cookies and assorted drug paraphernalia.

When Edgren was arrested, he was carrying a duffel bag with about a half-ounce of liquid LSD, 55 grams of marijuana, 5 grams of hashish, 60 Adderall pills, a laptop computer, two digital scales and $400 in cash, authorities said.

Edgren, of Princeton, faces multiple drug possession and distribution charges. He is free on $25,000 bail.

Lt. Mike Novembre estimated that the street value of the seized drugs is $400 for the psilocybin, $420 for the Adderall pills, $1,100 for the marijuana, $500 for the LSD, $280 for the ecstasy and $175 for the hashish.

Officers with the county prosecutor's office, the U.S. Department of Homeland Security and U.S. Customs and Border Protection, the U.S. Postal Inspection Service, the Princeton University Department of Public Safety, the county sheriff's office, New Jersey State Police, and the Hamilton, Lawrence, Princeton and Trenton police assisted in the investigation.

Cristina Rojas may be reached at crojas@njtimes.com. Follow her on Twitter @CristinaRojasTT. Find The Times of Trenton on Facebook.