Assistant Dean of Students Sarah E. Flatley said administrators are also working with proctors to encourage students to lock their doors and to be more diligent about allowing non-students to enter the building.

"Students should ask people who piggy-back them in for an ID card or for who they're going to see," she advised.

According to Nathans, students who lock their doors have taken the most important safeguard for their personal security and the security of their belongings.

"As we understand it, every recent incident in Matthews has involved easy entry through an unlocked suite door," Nathans said yesterday. "Locking suite doors may seem unfriendly, [but] the payback in personal safety strikes the Freshman Dean's Office as immeasurable."

Nathans wrote that she has also asked proctors to remind students to call HUPD immediately, should they see unfamiliar or suspicious individuals in dormitory areas.

Chris Dewing '95, a proctor on the first floor in Matthews, said the facts that yesterday's trespasser was arrested and that the exterior doors now shut more quickly have made students feel much more comfortable.

He said students have been receptive to requests to lock their doors.

"People are looking out for each other a little bit more," Dewing said. "But I don't think there's been too much fear. It's more of an acceptance of what we have to do to keep things safe around here."

Yesterday's incident is the latest in a string of break-ins in Matthews.

Police arrested a man last week who allegedly walked into a first-floor suite and into the second-floor suite of Nicholas J. Saunders '99.

"I was sitting at my desk when the door starts opening and this guy looks in," Saunders said. "He tried to shut the door, but I came out [into the hallway] and he said, 'I'm just looking for my friend,' with an attitude."

Harvard police were notified of the trespasser by a friend of Dewing's and arrived quickly, Saunders said.

According to Saunders, police said the man was on parole for trespassing and was drunk and claimed to be looking for a bathroom.

Last fall, a trespasser entered an open fourth-floor suite in the early morning hours and emptied a student's wallet. In a separate incident, a bicycle was stolen from a first-floor resident.

"Toward the beginning of the year we had the door open in the early hours, but we're pretty scrupulous about keeping it shut now," said first-floor resident Matthew J. Lutch '99, who said a trespasser took over $30 from his suite one night in November.

Lutch said he welcomed locks on bathroom doors, though he was unsure whether they were necessary or not.

"But at this point," he said, "We'd rather be safe than sorry.