It happened on Wednesday, Aug. 7, around 5:40 a.m. at the A Line's Allen Station.
Warning: The video above contains scenes that some viewers may find disturbing.
The video shows the man, who's been identified as 33-year-old Juan Pablo Flores, kicking and dragging the woman into oncoming traffic along the 210 Freeway. At one point, he tossed her so close to the main lanes, she was almost hit by a passing vehicle.
"I've never seen anything like this, especially in Pasadena," said resident Christopher Martinez when he was shown the video. "That's crazy."
The victim suffered a broken nose and damage to her head and face.
The Los Angeles County Sheriff's Department said her injuries have "potential for long-term disfigurement." Flores was arrested shortly after the attack.
Authorities said he and the victim did not know each other, saying the incident was completely random.
Flores has since been charged with two felonies: one count of attempted murder and one count of mayhem. He's currently being held on $2 million bail.
"Our thoughts are with the victim and her loved ones as she begins her journey toward recovery following this horrific attack," said L.A. County District Attorney George Gascón in a statement. "No one should have to endure such brutality, and everyone deserves to go about their day without fear for their safety. We will not tolerate violence on our transit system and will continue holding those responsible fully accountable for their actions."
If convicted, Flores faces a maximum sentence of life in prison.
Leaders speak out
Los Angeles County Supervisor and Chair of the Metro Board of Directors Janice Hahn issued a statement shortly after the attack earlier this month, calling the incident "disturbing."
"I am grateful that the victim is recovering and that the suspect is in custody," she wrote. "Our board will need a full investigation into this incident, an accounting of where both Metro's contracted law enforcement and transit security were when this woman was attacked, and a plan to increase security during early morning commuting hours. Our trains, buses, and stations must be safe for our riders and we have to continue to implement safety reforms to get our system to that point."
Los Angeles County Supervisor Kathryn Barger also issued a statement, saying she's "outraged" to hear of another attack on the Metro system.
"I want to commend the transit deputies who responded quickly and apprehended the suspect.
This incident is a perfect example of why we need to urgently address safety issues, not only on the Metro train system, but also at stations. I expect a full report from Metro on what security measures will be put in place to increase security, especially during early morning commute hours.
Our Metro Board has already taken some steps to improve public safety, including enforcing fares. But, it's obvious to me that our Metro system commuters are still confronted with serious safety issues that cannot be ignored."