Harvard Medical School student Raul Ruiz could spend up to three years in jail after his arrest during a Thanksgiving Day protest last fall.

Ruiz--who argues that the celebration of Thanksgiving is disrespectful to American Indians--was charged with two misdemeanor offenses, disorderly conduct and tumultuous behavior.

He pled "not guilty" to both offenses after the incident.

Ruiz's next trial date is now set for April 15.

Plymouth Police Captain William A. O'Mara said Ruiz was among 25 demonstrators arrested after they refused to leave Plymouth streets.

Forty police officers used physical force and pepper-spray to disperse the crowd of 200 demonstrators.

No one was taken to the hospital, although two protesters did receive "cuts" on their heads during the scuffle, O'Mara said.

Ruiz said yesterday that the police used inappropriate force in controlling the crowd.

"The police were definitely out of control.... As people were being beaten and as children were being pepper-sprayed, I felt an obligation to help, not only as a [demonstration] leader but also as a future health professional," Ruiz said.

Michael L. Altman, Ruiz's attorney, agreed with his client.

"What actually happened...was a police riot," he said.

O'Mara denied allegations of police brutality. "You had a group of people who were just belligerent," he said.

"We feel they came there looking for a confrontation because they were looking for news media coverage," he said.

O'Mara added that four or five of the protesters were charged with assault and battery of a police officer.

According to Altman, 1997 was the 28th consecutive year of Thanksgiving Day protests in Plymouth.

The United American Indians of New England (UAINE) sponsors these annual "Days of Mourning" to speak out against American Indian mistreatment.

O'Mara said that, until last year, the demonstrations were usually peaceful and involved no marching.

"Last year, they moved out into the street... UAINE said they would return until Plymouth canceled its Thanksgiving celebrations," O'Mara said.

Ruiz, a Chicano, said he has participated in the UAINE protests for the last two years and believes that Thanksgiving celebrations are disrespectful to American minorities.

"[Thanksgiving] is the glorification of an incident in history which has a direct link to the...poverty and oppression which [Latinos and American Indians] experience today," Ruiz said.