By Karina Rusk
San Jose, CA (KGO/CNN) - A fun night out ended deadly for a young woman in California.
She and a group of friends were riding in a party bus after attending a Brad Paisley concert in Santa Cruz.
Suddenly, she and another passenger fell off the bus and onto a highway.
The young woman was run over and killed.
Specialists and investigators are taking a hard look at the door of the Santa Cruz party bus.
Natasha Noland, 25, died after she and a 20-year-old woman fell out of the bus Friday just before midnight.
The CHP says the door is an air pressure, or pneumatic system and not a mechanical or motor system.
"Did the door just fly open? Or did someone just trigger this mechanism or this pneumatic system that opens the door? We're just unsure of that now and that's what our investigators are doing at the tow yard today," said D.J. Sarabia with the California Highway Patrol.
Sam Lavasani has owned Nationwide Limousine Service since 1988, a company not involved in this tragic incident. He says emergency door levers are put in places where they generally cannot be triggered accidentally. He also says the position of the door on the bus involved is not adjacent to the driver.
"Because there is a front door already, the second door falls a little bit back which means it is close to where people are sitting, behind the driver," said Lavasani.
The CHP says Noland was in a group of 12-15 people coming back from a Brad Paisley concert at Shoreline Amphitheater in Mountain View. She worked at the Pacific Wave Surf Shop in downtown Santa Cruz, which her parents own.
"It's like surreal. I am expecting to get a text from her or something. It's pretty hard. It's not the same here without her," said her friend, Erik Witzig.
"I can't imagine what they are going through, but they need to know the whole city and everybody here is there to support them in whatever way they need," said Casey Protti, a downtown business owner.
The CHP says there was excessive drinking on board the party bus, and says it arrested two people at the crash site - a 19-year-old passenger and Noland's 33-year-old boyfriend, Bryan Larson.
"We understand how tragic this must have been for him, although, he acted in a manner where our officers couldn't do their job properly and actually assaulted one of our officers. So, he was taken into custody for his safety and for everyone's safety," said Sarabia.
California Highway Patrol officers say some of the party bus passengers took off before officers could interview them about what happened.
CHP says it's trying to track down those people now.