Three graduate students in the Mathematics Department on Friday discovered that their offices in the Science Center had been broken into and some of their valuables stolen.

"Friday morning about 10 a.m. I found my office in a big mess," said Ian C. Dowker, a third-year graduate student who is a teaching fellow for Math 1b this semester.

The thief or theives had taken his Discman and several CDs from Dowker's fourth-floor office. He said he did not have any other valuables in the office at the time.

Dowker said the intruders broke into the office of Randy Scott, another teaching fellow, on a different corridor of the fourth floor and stole Scott's laptop. They also entered the office of a fourth-year graduate student on the seventh floor in the Statistics Department, who noted the theft of a Walkman from that office but asked not to be named.

The students immediately reported the thefts to the Harvard University Police Department (HUPD), which estimated the cost of the stolen items at more than $2,000. The HUPD declined to comment about how the intruders entered the building.

"I can't assume anything [about when the break-in occurred]," said Peggy A. McNamara, spokesperson for the HUPD.

But the students have their own theories.

Dowker said that the thieves entered his office at 4:10 a.m. Dowker said that as they entered the office, they knocked his "Manchester United Football" clock off the wall. The batteries fell out, and the clock now reads the exact time of the forced entry.

The offices are all located along different corridors with ceiling paneling. On Friday morning, Dowker said he found one of the panels leaning against the wall. He said that a thief could have crawled through the hole created by the absence of the panel and entered the office by knocking out the paneling in its ceiling.

The HUPD is currently investigating the thefts.

McNamara said that thefts like this have never occurred before in the Science Center and that the HUPD does not plan to increase security in the building.

"I have not been made aware of any additional measures," McNamara said.

The students said they are not concerned about the safety of their possessions.