Wellesley College administrators have beefed up security and are continuing investigations in the wake of an alleged rape, officials said last Sunday.

A 19-year-old Wellesley undergraduate was allegedly raped on the morning of February 18, according to Wellesley College News Director Laurel Stavis.

The student said that she was sexually assaulted when she returned to her room by a man who she believes was hiding in her closet, said Wellesley Police Chief Thomas O'Loughlin. The student was unable to provide a description of the individual, O'Loughlin said.

The student also said that she had been sexually assaulted in her room six days earlier. Police are investigating a possible relation between these two incidents and a another, previous report made by the undergraduate of a non-sexual assault and battery on February 3, O'Loughlin said.

The alleged attacks have prompted a considerable boost in on-campus security. Student sensor cards, which open dormitory entrances, were reprogrammed by campus police, and students who have lost keys during the year received new locks on their doors, Sander said.

Sophomore Stacy Palestrant said she waited for an hour on Thursday at the campus police station to get her card reprogrammed.

"There was an atmosphere of apprehension among the students because we really weren't sure what was going on," Palestrant said. "The college really went all out on this."

Some undergraduates said yesterday they still have questions about what happened to the woman.

Junior Sharon A. Thompson said she was skeptical because of the nature of the alleged victim's reports. "It's very strange that she was attacked twice in one month," Thompson said.

Others called for the administration to release more details of the alleged incidents.

"The administration isn't saying much, and has only officially confirmed the incidents of the third and the 18th [of February]," said Catherine E. Sander, editor-in-chief of the Wellesley News.