The woman and her boyfriend boarded the No. 27 bus and tried to find a seat as it traveled through North Baltimore.
But a fight quickly broke out between the pair and a group of nine students heading home from their Hampden middle school, police said.
By the time Maryland Transit Administration police officers reached the bus along East 33rd in Waverly on Tuesday afternoon, the teens had punched and kicked the woman, dragging her out of the vehicle's rear door and leaving her with broken bones around her eye.
The nine students from Robert Poole Middle School, who are all 14 or 15, are charged as juveniles with aggravated assault and destruction of property. After juvenile hearings yesterday, all were released to their parents, directed to be kept under home detention and told to stay out of school until their next court hearing Jan. 4.
But yesterday, police and some of the youths' parents sharply disagreed on what sparked the after-school brawl -- which MTA officials characterized as a rare example of serious violence on the city's public bus system.
According to a police report, one of the boys kept jumping in front of the woman, Sarah Kreager, 26, and claiming that the open seats on the bus were reserved.
When Kreager finally found a seat, the teens began throwing punches at her and her boyfriend, according the report. The beating continued, police said, even as the eastbound bus lurched to a stop and the driver radioed for help about 3 p.m.
At one point in the Tuesday afternoon attack, police said the teens punched and kicked Kreager, broke down the rear door of the bus and dragged her into the street. The report says she suffered two broken bones in her left eye socket, two deep cuts on the top of her head and other cuts on her neck and back. Her face was bruised and her left eye was swollen shut.
Kreager was taken to Maryland Shock Trauma Center. Her companion, Troy Ennis, also was beaten, police said, but did not require hospital treatment.
But the mother of one of the suspects says the victim, for an unknown reason, provoked the attack by spitting in the face of one of the girls. Beverly Bell, whose son is an eighth-grader at Robert Poole, said the victim's boyfriend then pulled out a knife and threatened the girls, which prompted the boys to attack the man.
Interviewed after yesterday's court hearing, Bell said her son had never been in trouble before. Testimony in juvenile court revealed that five of the six boys arrested had no juvenile records.
"We don't know why that woman did what she did," said Bell, referring to the alleged spitting incident. "But I can't see these kids jumping on anyone for no reason."
Another parent said it was Kreager who did not want any students sitting next to her initially, prompting an argument.
Edie House, a spokeswoman for the city school system, said yesterday that the fight is "under review" by school police.
"We're getting conflicting reports about what actually occurred on the bus," she said. "We've not had a chance to speak to the students who were arrested. Once we do that and complete our investigation, we will determine what disciplinary action is going to be taken."
MTA officials also are investigating. "This agency is looking at this as a very tragic event," said Jawauna Greene, an agency spokeswoman.
State officials characterized the attack as an isolated and rare act of violence on city buses that was quickly brought under control by police. Crime statistics were not available from the MTA.
Greene said the agency is reaching out to schools, parents and students to let them know that riding city buses after school is a privilege that can be revoked. "If there is a silver lining in this, it's the fact that the bus driver's response was timely, and he knew the proper steps to alert authorities to prevent the loss of life," Greene said.
MTA officials said about 30,000 children in Baltimore and Baltimore County use the subsidized bus service.
The bus dispute is the most recent in a series of local fights involving teenagers.
Late last month, a brawl in Edgewood left a man paralyzed after he was assaulted with a baseball bat and kicked by at least six juveniles, according to Harford County sheriff's deputies.
A few weeks earlier, city and schools police arrested 22 girls involved in a melee that sent one student to the hospital with minor injuries after a high school football game at M&T Bank Stadium.