Transit police in Boston announced the arrest of a 16-year-old male in connection to an alleged racially motivated assault on a woman of Asian descent on the Red Line near the JFK/UMass stop in an incident that was caught on tape.

The arrest on Monday was in relation to an alleged assault that occurred on Sept. 21. The investigation is ongoing, and charges will be sought, according to a statement released by the Massachusetts Bay Transportation Authority Transit Police on social media Tuesday.

At around 11 p.m. local time, several juvenile male passengers aboard a Red Line train near the JFK/UMass stop "were harassing, threatening to rob passengers & taunting individuals allegedly based on their ethnicity," MBTA said in an initial statement announcing the attack.

Police said that the group of juveniles "smashed out" the train window and fled and shared pictures of the broken glass in a post on "X", the platform formerly known as Twitter.

In an update posted to social media on Tuesday, MBTA announced that Forest Hills Station detectives and officers assigned to the Criminal Investigation Unit arrested the unnamed 16-year-old male on Monday for "assault to rob-unarmed" and "assault for the purpose of Intimidation."

"The TPD would never confirm a victim's identity and or a witness. This is an ongoing investigation involving juveniles and we do not have a comment at this time," the MBTA Transit Police told ABC News in a statement.

While the police did not name the victim or victims in this incident or indicate their ethnicity, part of the incident was captured on video by Vivian Dang -- a woman of Asian descent -- who identified herself as a victim in an interview with ABC News on Thursday.

Dang, 25, told ABC News that on the night of Sept. 21, she was riding the Red Line home after having dinner when a group of five or six juveniles got onto the train and announced that this was a "mass robbery," while laughing and appearing to make light of the situation.

She said that one of the juveniles complimented a man's shoes and after he said, "thank you," and then he allegedly tried to shake the man's shoes off his feet.

"When started getting physical, I was like, you know, I had to get out of there. And so I waited until the next stop for me to switch carts," she said.

But then the group followed her to the next cart, according to Dang, and "that's when they started to pick on me," she said, "because they realized that I had moved carts to, you know, avoid them."

"They started calling me a lot of derogatory terms, and then -- and then it started to get very racist," she said. "I was just trying my best to ignore them ... avoid them as much as they can and go home. But yeah, it just started happening like so fast. And the trains were just slow that night. So even though it was just only [a] few stops, they were just saying it for like the longest time."

Dang said that as a woman of Asian descent, there have been times when racist comments were directed towards her, but never to this "severity."

"It was the first time that I was truly the one being attacked," she said.

According to Dang, after a woman confronted the group in an attempt to defend Dang, the juveniles began making fun of the woman's accent and yelled at her.

Asked what compelled her to speak out, Dang said while she initially wanted to "stay quiet" and just go home, it was the woman who spoke up for her on the train who encouraged her to speak with the police who arrived on the scene.

"She really wanted me to say something and she really wanted to help me," she said. "She wasn't trying to get anything out of it. But she wanted to help ... so she had literally gotten the police to come over to my cart and speak with me."

Dang filmed part of the incident on her phone and shared it with police before posting it on her own social media account when she got home. When her sister, Vanessa Dang, posted the video on her TikTok account, it got more views and went viral.

In the 1-minute clip, a group of Black juveniles – one of whom was wearing a mask – appear to mock the accents of people of Asian descent and when confronted by others on the train, they appear to yell back at them.

"They cornered me, harassed me, made very inappropriate comments, when people started to defend me they got attacked as well, as seen in this short clip, it all happened so fast," Vivian Dang said in the text that appears on the video.

Dang said that while she initially wanted to "just go on with my day and go home," after she reflected on what happened, she decided to speak out.

"If I were to see this happen to someone else I would, I would 100 percent speak up and say something," she said. "And, you know, I also wanted to point out that it was this woman that had stuck up for me and helped me."

"I realized that, you know, it, everyone should be able to speak up and say something when they're seeing any type of injustice," she added. "Now that this is happening, and it's reaching an audience, I would hope it's spreading awareness for people to stick up for each other, especially those that can't defend themselves."