An e-mail urging Harvard students to maintain “free expression” on campus hit students’ inboxes earlier this week—but with no indication of the motivation behind the message.

Interviews with administrators and student group leaders revealed that the letter came as a response to what a College dean termed “serious and persistent instances of vandalism” directed at Harvard Right to Life, an anti-abortion student group known for its frequent political publicity campaigns.

The message, sent by Associate College Dean Judith H. Kidd and delivered via all 12 House e-mail lists, stated that “some students have taken it upon themselves to deface, cover or tear down posters with which they do not agree,” and pointed to a 1970 resolution mandating free speech at the College.

The e-mail did not cite any instances of wrongdoing inflicted upon a specific group.

But Kidd emphasized in an interview following the delivery of her e-mail that the letter was written “in response to a number of incidents, including those reported by Right to Life.”

In another e-mail sent to House masters and obtained by The Crimson, Kidd apparently said that while vandalism of HRL posters has occurred occasionally in the past, “This year is the worst I have seen.”

“We’d been noticing that a lot of our posters had been torn down or postered over recently,” said HRL President Mary Anne Marks ’10, adding that the group contacted the administration early this week to complain.

Marks said that an informal study conducted by a member of HRL found that each week, nearly one-third of the group’s posters had been removed or completely covered by other flyers. Marks added she was unsure if the posters had been defaced out of malice or mere coincidence.

Assistant College Dean Paul J. McLoughlin II said that although the complaints of HRL were “a part of the impetus” for sending out the letter to the College, the administration’s push for free speech on campus should not be interpreted as support for one particular group’s publicity campaign.

“We’re not just trying to protect HRL’s message, we’re trying to protect the freedom of expression for all student groups,” he said, differentiating between the group’s most recent complaints and those it has made in the past.

This time, he said, the complaints were representative of a recent spike in vandalism that necessitated a campus-wide announcement.

McLoughlin said that this increase in vandalism has impeded the publicity efforts of other student groups, as well as the Student Life and Activities Office. He said that the entire side of a sandwich board filled with the office’s posters—intended to remind student groups of a registration deadline—had been quickly removed to make way for other groups’ ads.

McLoughlin said he did not know who ripped down the posters.

“We’re not there policing the posters,” he said. “Guarding them would be an impossible task.”

—Staff writer Charles J. Wells can be reached at wells2@fas.harvard.edu.