Wellesley College senior Hadley Smith began the night of April 12 with her hands full of rainbow-colored chalk and ended it in the town police station.

As part of the Wellesley College Peace Coalition, Smith, 22, and other students spent the early evening scrawling onto the town center's sidewalks peace signs and quotations from Mohandas K. Gandhi.

Someone followed them back to their dormitory, copied down the license plate number of the car Smith was driving, and contacted Wellesley police, according to the police report.

That led to an evening in jail for Smith and her fellow students, an experience that has led to misgivings on the campus of 2,300 students about the way police handled the incident. A spokesman for Wellesley police said the students were not mistreated.

Smith, a senior history major, said she was back in her dormitory room the night of April 12 when she got a call on her cellphone about the chalk from a detective on the town police force.

''He said I better get back there and that the faster I did that, the better off we would be," Smith said.

Smith, of Rochester, N.H., along with students Justine Parker, 21, of Chicago, and Kate Recchia, 20, of New Haven, returned to the town center, where they were met by Detective Peter McLaughlin.

According to Smith, McLaughlin gave the women a choice between arrest and cleaning up the chalk. Smith says when they asked for clarification of their offense ''he said it was not up for discussion. We told him, 'We're going to clean it, but we're trying to understand why we'd be arrested.' And he was like, 'Nope, you've lost your chance.' "

McLaughlin did not return phone calls. But Marie Cleary, public information officer for the Wellesley police, said the women were informed by police why their actions were illegal. They were charged with ''defacement and tagging public property."

''I'm not sure which of the young women disagreed and began to debate the issue," said Cleary. ''But at that point, the officer determined that he would place them in custody."

The next morning, after several hours in a holding cell before being released on $40 bail -- a friend bailed them out -- the three women were arraigned in Dedham District Court. In exchange for three months probation, 12 hours of community service, and a $63 fine, all three will have their records expunged.

Parker, a junior who is president of the campus Peace Coalition, said word of the students' encounter with police traveled fast. Soon after, college officials held an open meeting for students and faculty to discuss the incident. Janis Vogel, 21, a Wellesley senior who said she was troubled by the arrest, estimated that about 30 students and professors attended.

''That's big for the kind of crowd you usually get at Wellesley," she said. ''A lot of professors expressed their concern."

With a month to go until she graduates, Smith said the incident was an intimidating introduction to a criminal justice system she had previously experienced only through books.

Smith said that students are able to write messages in chalk on their campus and that she didn't think their sidewalk writing was against the law. She says she now understands that chalking is illegal.

Parker said college administrators suggested that students start up a dialogue with local police, but she has not followed up on the idea and has encouraged angry students to put their energies toward peace activism instead.

''Our encounter with them demonstrated that they're not interested in dialogue," she said. ''I'm not giving up on them, but it was a very intimidating experience."

© Copyright 2006 Globe Newspaper Company.