Fresno County sheriff's officials say they were used to help treat two men who were shot here just after midnight.
19-year-old Edgar Chavez died on scene. The other victim was taken to Community Regional Medical Center in critical condition.
"All I did is I heard 6 shots. I came out, saw a lot of people spreading out, running out scared. There was a kid on the ground with a shot to his heart."
Just before the shooting, witnesses claim about 200 teens were hanging out and drinking near the vineyard.
Detectives say the gathering grew out of hand after organizers promoted the party on social media networks, such as MySpace and Facebook.
While some neighbors say the area is known for such gatherings, others tell Action News this latest incident will likely deter any more from happening.
"I aint worried about it. It's peaceful. It's quiet. It's an incident that happened. No more parties here. Let me tell you."
Fresno county investigators have not released a motive in this case nor have they named any suspects. The hope now is that someone will eventually come forward.
"I just feel sorry for the parents. That's all I can say. I just feel sorry for them."