The beating of a teenager on a subway in Philadelphia this week has reignited fears in the city’s Asian communities about racially motivated violence, and it’s left some students worried for their safety commuting to and from school.

On Friday, the family of the 18-year-old Asian American student who was assaulted in an incident caught on video said they are traumatized after the “unprovoked, brutal attack.” Mei Lu, the teenager’s aunt, said her niece was beaten because she intervened when she saw girls yelling at three Asian boys and using racial slurs.

“Her heroic act, her altruistic act, came with a big price,” said Lu, who spoke in front of about 100 supporters at the Chinatown Community Center. Her sister, the teenager’s mother, wept as Lu described the victim’s injuries, which included extensive bruising and swollen eyes.

She said the teenager, a senior at Central High School, is still undergoing tests to determine the severity of her head injury.

On Thursday, the District Attorney’s Office filed aggravated assault and ethnic intimidation charges against four teenagers who officials said range in age from 13 to 16. They were charged as juveniles and have not been publicly identified.

SEPTA Police Chief Thomas Nestel III said the four, a group of Black girls, can be seen on video yelling at three teenage boys of Asian descent, who are students at Central High School. Then the 18-year-old student stepped in to defend the boys, and the girls turned their attention to her, banging her head against the subway door then beating her as she lay on the floor.

The assault has left some students and parents, especially those of East and Southeast Asian descent, worried about safety. Across the country, Asian Americans have reported a rise in harassment and racially motivated violence since March 2020, the beginning of the coronavirus pandemic. In Philadelphia, reports of anti-Asian American hate incidents tripled between 2019 and 2020.

Carlie Zhang, a Central senior and a friend of the victim, said the school’s large Asian community is shaken after 18 months spent attending school via computer, the cumulative effects of COVID-19, and growing animus toward Asian Americans.

”A lot of us are really struggling, traumatized,” said Zhang, 17. “We see our own friends, people who look like us, getting hurt, getting beat up.”

» READ MORE: Philly Asian Americans have experienced a year of hateful acts, and fear it’s going to get even worse

But she said Central’s Asian students don’t want the incident to “cause a divide between the Black and Asian communities.” She hopes the spotlight helps bring positive change, like stronger mental health services and more counselors at all Philadelphia schools.

”We can’t just solve this one issue and call it a day,” Zhang said. “We need to make sure these instances don’t happen again.”

On Thursday, Central principal Timothy J. McKenna wrote in a letter to parents and the school community that the school is providing extra counseling and support services to students feeling anxious or concerned for their safety. He also said he met with parents and community advocates to create a plan to ensure that students can safely travel to and from school.

“We need to pressure our political and law enforcement leaders to develop plans that keep all members of our city safe,” he wrote.

At-large City Councilmember Helen Gym said the incident shows that “we as a city and a nation are not doing nearly enough to support young people.” She said to address the root causes, the city and school district should pour more resources into mentorship programs as well as job and recreational opportunities.

“There’s no question that they are emulating what they’re seeing, especially in terms of the violence and the scapegoating, in particular,” Gym said, adding: ”They are trying to articulate out what they need to see done better by institutions, including the school district, to address racial bias, intimidation.”

Following the incident, SEPTA assigned a police officer to monitor the Broad Street Line train leaving from the Olney station as Central discharges students each day. A spokesperson for the transit agency said SEPTA will evaluate the change and may consider similar moves on other trains or in other locations.

John Chin, executive director of the Chinatown Development Corp., said the move is “a good start” but that parents and community members remain concerned about safety after what he described as “20 months of hate, violence, assault, harassment.”

Lu said her niece is a passionate social-justice advocate who said that if she had a chance to go back and do it again, she still would have intervened.

“She stood up. She had her voice heard,” Lu said. “She was at the right place at the right time, doing what she can.”

Inquirer staff writer Ximena Conde contributed to this article.