AUSTIN, March 28 -- Civil rights activists are rallying around a 15-year-old black girl who has been in a high-security juvenile detention center for a year for shoving a hall monitor at her school and whose sentence was just extended for what authorities call possession of contraband: an extra pair of socks and a plastic foam cup.

One of 4,562 juveniles in the Texas Youth Commission's custody, Shaquanda Cotton may have remained incarcerated in obscurity, fretted over by her mother and a handful of supporters in her home town of Paris, in northeast Texas near the Oklahoma border. But a Chicago Tribune article has prompted an inquiry by the Rev. Al Sharpton and spurred several hundred protesters to travel this week from Dallas to the courthouse where Cotton was convicted. Internet message boards and blogs have been flooded with postings crying "Free Shaquanda Cotton!"

Almost every bit of information in the Cotton case is in dispute -- from the allegation that on Sept. 30, 2005, Shaquanda shoved a 58-year-old white teacher's aide acting as a hall monitor to whether her mother was offered the opportunity keep the teenager at home under the less-onerous option of probation.

Her mother, Creola; the state NAACP; local African American activists and a few white lawyers in Paris contend that the girl and her mother are victims of a discriminatory school system.

They say that the Cottons have been targeted by the Paris school district because of Creola's involvement in a group that complained to the U.S. Department of Education about discrimination against black students. A spokesman for the Education Department said it is investigating whether the district discriminated during the 2004-05 and 2005-06 school years "in the administration of its discipline policies."

Cotton and her supports also say a white judge who gave a white 14-year-old girl probation after she was convicted of burning down her family's home treated Shaquanda unfairly.

Representatives of the Paris school district and the criminal justice system adamantly dispute the allegations. Lamar County Judge Chuck Superville, who sentenced Cotton and the arsonist, was not available for comment. But a spokesman for the Lamar County district attorney's office addressed questions.

"This girl was adjudicated delinquent by a jury . . . on assault of a public servant," Allan Hubbard said about Shaquanda. "She pushed the teacher down, and anyone who does that will continue to be prosecuted to the level of the law that is allowed under the Texas Family Code. It doesn't matter what color they are."

Hubbard said that Shaquanda was offered two years' probation if she pleaded guilty to a misdemeanor assault, a plea deal that Creola Cotton refused because her daughter, who has no previous criminal history, said she did not shove or push the teacher's aide. Hubbard said that after a jury trial on the felony charge of assault on a public servant, the judge sentenced Shaquanda to a minimum of a year in a youth facility because the mother would not cooperate in establishing home-supervised probation.

Creola Cotton disputes that allegation. That issue is among several raised in the appeal of Shaquanda's conviction to the 6th Court of Appeals of Texas. "The judge sentenced her and he didn't have sufficient evidence to show there was not an alternative" to the youth facility, said Gary Waite, the attorney handling the girl's appeal. "The evidence was legally insufficient to establish that her mother couldn't provide the care and support to meet conditions of probation."

Gary Bledsoe, president of the Texas chapter of the NAACP, called the circumstances of Shaquanda's incarceration "abominable."

"It's a clear miscarriage of justice. If you take the accusation, there is no way a colorblind court system would have allowed that situation to go forward," he said. "The facts don't justify the punishment. It is clearly excessive and has really harmed this young girl."

A spokesman for the Texas Youth Commission, an agency recently turned over to a conservator because of long-ignored allegations of sexual abuse of incarcerated juveniles by facility employees, said the extension of Cotton's sentence will be examined. Youth facility supervisors can extend a juvenile's sentence until he or she turns 21 for any number of infractions. About 45 percent of the more than 4,600 juveniles have received extended sentences in recent years. Allegations have been made that sentences were extended arbitrarily and to intimidate teenagers.

Although forbidden by law to comment on a specific juvenile, Youth Commission spokesman Jim Hurley said that "the publicly cited case of someone getting a term extended for having contraband which turned out to be an extra pair of socks is indescribable. It is beyond belief, if it is true, and we will have a panel reviewing each of these cases."