SAN FRANCISCO (KRON) – The San Francisco Municipal Transportation Agency is launching an investigation after a full-blown fist fight on a bus was captured by an eyewitness on their cell phone camera.

Officials tell KRON 4’s Jonathan Bloom the incident happened Wednesday around 10 a.m. all the way on the back of a 20-Columbus Muni bus.

After several minutes of yelling obscenities at each other, video taken by an amateur photographer shows two women throwing punches at each other as several passengers looked on.

While a younger woman stepped in to break up the fracas about 30 seconds after fists started flying, the two did not stop fighting easily.

Muni spokesperson Judson True tells Jonathan they do not believe the fight was reported, “So this is a case where if I was on a bus I might call 911 or something like that. We don’t know that they didn’t, that no one did, but it does seem like they might not have.”

The amateur video, however, shows a Muni employee standing just outside the bus after the fight. The transit agency says the driver never radioed in to report the fight.

And according to True, this would be a violation of Muni’s rulebook, “Any Muni employee that would see something like an assault going on and not report it, that’s not appropriate and we would handle that, you know, as we should.”

Due to all the questions swirling around this incident, the transit agency is launching an investigation that could result in disciplinary action.

True says they already have the bus number and are questioning the driver.

This was a very long bus, 60-feet long, the kind that bends in the middle. So officials say it is very possible the driver did not know the fight was happening.

Muni says its investigation will be focused only on whether the driver or other transit employees did something wrong by not reporting the incident. As for the two women involved in the fight, officials say that it’s up to police if somebody decides to press charges.

(Copyright 2009, KRON 4, All rights reserved.)