ATLANTA -- "Soulja Girl" is behind bars.

MARTA police said Nafiza Ziyad, 25, is the woman caught on video during a profanity-laced tirade on a MARTA train.

VIDEO: Verbal Attack On MARTA Train

Captured by another rider the video of the woman's rant, directed at an elderly MARTA rider, has become an Internet sensation, getting heavy viewing on YouTube.com and other Web video sites.

During the confrontation the young woman refers to herself as "Soulja Girl," repeatedly uses the N-word and threatens an elderly woman.

After getting tips identifying the young woman as Ziyad, MARTA police charged her with simple assault and two counts of disorderly conduct.

Investigators told WSB-TV Channel 2 reporter Tom Jones they were able to identify the elderly passenger and after speaking with her they arrested Ziyad. Her mother told WSB-TV's Monica Pearson Ziyad is bipolar and was off her medication when the attack took place.

VIDEO: 'Soulja Girl's' Mom Says She's Bipolar

"I was shocked," said Ziyad's mother, Elaine Sabree. Sabree told Pearson her daughter was off her medication because, "She didn't believe she was bipolar."

At first other passengers don't interfere during the minutes-long attack, but finally one man can be heard telling "Soulja Girl" to "chill." Instead of taking that advice she turns on the other passengers, accusing one of rape.

Eventually a male passenger confronts her and appears to knock her wig askew.

After repeatedly screaming "I'm pressing charges, I'm pressing charges," the woman exits the train.

After learning of the video MARTA police launched what they called "an immediate and aggressive investigation into the incident."

"I pray this is a wake up call for her," said Sabree. "Someone could've gotten hurt."

MARTA officials said they will work with the solicitor general's office to prosecute Ziyad to the fullest extent of the law.

The elderly woman has been identified as Mary Freeman. Freeman's son, Richard Freeman, is the head football coach at Morehouse College. He told Pearson his mother doesn't want to go on camera because she, "doesn't want to make the girl feel bad." He said his mother was never angry at the young woman and Freeman knew Ziyad was troubled.