Elizabeth Okazaki had made herself at home in Stanford's Variant Physics Laboratory, where she used computers, attended seminars and sometimes spent the night, students told the San Francisco Chronicle.

Stanford officials were taking steps to keep Okazaki off campus. Attorneys were preparing a letter notifying her that she is not allowed on campus while police and university officials investigate her actions, spokeswoman Kate Chesley told the newspaper.

Undergraduate physics student Brendan Wells, 22, said that Okazaki is harmless.

"A lot of what she does is just use the computers, make tea and just kind of use the space as a place to be," Wells told the paper. "I don't know if that's because she doesn't have somewhere else to go or she prefers it here."

Earlier in the week, campus officials revealed that an 18-year-old woman, Azia Kim, had passed herself off as a freshman for most of the school year. She had convinced students to let her room with them in two separate dorms for about eight months.

Greg Boardman, vice provost for student affairs, said the university was launching a sweeping investigation into the Kim case, including "seeking to discover where there may be gaps in Stanford's system of identifying enrolled students."

Both cases are being investigated by Stanford police and campus officials.