Investigators say they don't yet know why a gunman opened fire on a Greyhound bus packed with passengers on a Southern California highway.
A 51-year-old woman from Colombia was killed and five people were wounded Monday. Two of them were critically injured.
A 33-year-old man from Maryland has been arrested. A passenger says the gunman had been sitting with his leg sticking into the aisle and was muttering incoherently.
Then he began cursing and shooting.
Authorities say passengers managed to disarm the man and get him off the bus that was heading from Los Angeles to San Francisco. That bus driver then drove to the next exit and parked in a gas station, where those injured received treatment.
The suspecred gunman reportedly left the weapon, a black handgun, on the bus.
Authorities later took the man into custody.
