University police will interview a Saybrook freshman today who said she was given a date-rape drug at an on-campus party two weeks ago.

The student, who asked that her name not be disclosed, said she believes someone put a date-rape drug in her drink at a Yale Hellenistic Society party in the Berkeley Bagel Bar April 2. Police opened an investigation into the claim Wednesday, Yale police Lt. Michael Patten said.

The allegation is extremely unusual, Patten said.

“To my knowledge, there has never been a case, substantiated by chemical analysis, involving so-called ‘date rape’ drugs reported to us,” he said.

The investigation is still in its early stages and it is too soon to tell if the complaint is credible, Patten said.

The student said she was at the Berkeley party from about 11:30 p.m. to midnight and had only one drink.

“I just remember leaving the drink on the table to go upstairs to make a call, and coming back down to it,” she said.

The freshman said she felt “very drunk” when she left the party, though one drink ordinarily would not have affected her. Santiago Suarez ’07, a friend who met up with the freshman after the party, said they both then attended a party in Silliman College. After a brief time at Silliman, Suarez said he decided to take her back to her room.

“I have seen her drunk before, and she was acting excessively weird. It was completely abnormal behavior,” Suarez said.

The student said she remembers nothing from the night of April 2 after the walk to Silliman except a fall from her bunk bed during the night. She said she was vomiting frequently the next morning and was somewhat incoherent.

A doctor at University Health Services told her Saturday that she had probably been given a date-rape drug, but that it was too late to test for the presence of drugs in her system, the student said.

Patten said it is difficult to prove someone was given a date-rape drug.

“It’s difficult to establish that because there’s a very short testing window,” Patten said. “It’s metabolized by the body.”

Suarez said he was shocked when he was told his friend probably received the drug from someone at the party.

“It was a party where you know probably 80 percent of the people there,” he said.

Panayiotis Kalogeropoulos ’05, the president of the Hellenistic Society, said there were about 150 people at the party at the time the incident is alleged to have occurred. Kalogeropoulos said he was positive no one from the Hellenistic Society, a group celebrating Greek culture, would have given a date rape drug to the student.

“It definitely wasn’t anyone from our club. I personally know all the members of our board,” Kalogeropoulos said. “I personally acquired all the alcohol.”

Kalogeropoulos is a staff photographer for the Yale Daily News.

Patten said University police only have received one report of rape or attempted rape every year since 2000.

The alleged victim said she e-mailed police last week about the incident, but the officer she contacted was on leave. She forwarded the e-mail to Yale Police Chief James Perrotti Wednesday.

The student said she would strongly consider pressing charges against the person who gave her the drug, but she thought it was unlikely police would be able to solve the case.