By CBS13 Staff

COLUSA (CBS13) — A longtime Colusa County farmer and his wife were among the four people killed in a helicopter crash over the weekend, his family confirmed on Monday.

Bill Vann, his wife Susie, and two of their friends died in the Sunday afternoon crash near Highway 45 at Reservation Road. The sheriff’s office said first responders to the crash site pronounced the victims dead at the scene.

READ MORE: Cal Fire Says Fall Is Most Critical Time During Fire Season

The Vann family are well-known almond farmers who have called Colusa County home since the early 1900s. Their company now farms more than 17,000 acres in the Sacramento Valley.

“His loss is a shock to our family, our employees and our fellow growers,” said Garnett Vann, Bill’s brother and business partner, in a statement.

READ MORE: Mystery Man With Amnesia At UC Davis Med Center Identified Thanks To Community Tips

More than 200 people are employed by the Vann organization, the family says.

Garnett says the company will press on.

“Despite this tragic accident, the business will continue to move forward as we have been planning for the future for quite some time,” Garnett said.

Walt Seaver attended school with Bill Vann. He also owns the tomato field where the helicopter crashed.

“Yeah, it drives it home a little bit closer it’s tough, it’s a tough thing,” said Seaver. “It’s something I’m trying to deal with. I can grieve, I can feel loss, I can feel sorrow for the family but there’s something else there that’s bugging me, and I haven’t (been) able to identify it, and when I do I’ll deal with it but there is a definite sense of loss.”

On Monday, the Colusa County Sheriff’s Office also identified the other two passengers killed in the crash as 62-year-old Williams resident Bobbie Lee Keaton and 71-year-old Rocklin resident Charles Thomas Wilson.

MORE NEWS: Turlock Man Among 4 California Militia Members To Plead Guilty To Conspiracy

Exactly what caused the helicopter to crash is under investigation by the FAA and NTSB.