The Federal Bureau of Investigation will examine charges that Princeton admissions officials gained repeated, unauthorized access to the admissions decisions of 11 Yale applicants by hacking into Yale’s online admissions notification system.

Yale officials filed the complaint with the FBI Thursday after an investigation found that the University’s online notification Web site had been accessed 18 times from computers at Princeton, including 14 times from within the admissions office. Stephen LeMenager, Princeton’s associate dean and director of admissions, told the News Wednesday that officials in his office had accessed the site using social security numbers taken from the students’ applications to Princeton.

Princeton officials said Thursday that they would conduct their own investigation, involving outside participants, and that they had placed LeMenager on administrative leave for the duration of the investigation.

“We take this matter very seriously, and we are investigating it as quickly and as thoroughly as possible,” said Marilyn Marks, Princeton’s director of media relations. “The improper use of information provided to the university in good faith may have affected the ability of students to obtain information about their admission to Yale, something we deeply regret.”

Lisa Bull, a spokeswoman for the FBI in Connecticut, said the bureau will investigate the matter to determine if Princeton violated any federal laws.

Yale officials learned of the security breach after Princeton admissions officials mentioned it informally during an Ivy League deans’ conference in June. The University then commissioned an investigation, which was conducted by Alexander Clark ’04, a Yale undergraduate who designed the admissions site.

The investigation showed that users in the Princeton admissions office accessed the records of 11 students, four of whom had not yet checked their admissions status when the Princeton officials logged in with the applicants’ private information.

Legal experts said the use of students’ social security numbers may constitute a violation of the Family Educational Rights Privacy Act, which was designed to safeguard student information.

If Princeton is found to have violated the act — commonly known as the Buckley Amendment — the university could lose limited federal funding.

Yale General Counsel Dorothy Robinson said in a statement that the University had notified the applicants of Princeton’s actions.

Yale President Richard Levin said he felt confident in the Princeton administration’s response to the allegations.

“Obviously it is a situation that we deeply regret, that the Princeton admission office got into that mess,” Levin said. “But I think that Princeton will follow through, and I knew that the top level at Princeton is taking it very seriously.”