Woman killed, 4 people injured, taken to hospital, after two cars strike a horse and crash, on Idaho State Highway 16 near Eagle.

The female driver of a Honda passenger car has died after crashing into a horse, veering off the road, then hitting a rock wall Monday morning.

The deadly crash happened on Idaho State Highway 16 near the Firebird Raceway just after 5 a.m.

Ada County Sheriff's deputies say the woman was driving southbound when she hit the horse. Afterward, she veered off the highway, drove about 300 yards through fields and fences, and eventually struck a rock wall. The vehicle suffered heavy damage.

Police said it wasn't immediately clear if the woman died of injuries sustained when she hit the horse or after the resulting crash with the wall.

Deputies say the woman's two passengers were taken to a nearby hospital with unspecified injuries. They're expected to survive.

According to reports, another passenger car traveling southbound came upon the scene moments later. That vehicle hit the same horse and then flipped over. We're told the two people inside that car suffered minor injuries. One was transported to the hospital.

A bystander who wished to remain anonymous stated that she saw the second crash and quickly stopped her car to call 911.

"I had to call the police. I was looking for my phone. My purse went flying, so I was looking on the floorboard for my phone as fast as I could. And I had to get to the car to make sure everybody was still alive."

Law enforcement officials closed down both lanes of Idaho State Highway 16 near the crash site for nearly four hours as deputies investigated the crash and cleaned up debris. The highway was reopened just after 9:30 a.m.

Deputies believe two horses were able to escape a fenced area near Firebird Raceway before one was struck and killed in the crash.

In Idaho, livestock owners aren't responsible for keeping their animals off roadways in open range areas.

However, both animals were found wandering outside their pasture on closed range, according to a Ada County Sheriff's Office spokeswoman.

Furthermore, Dearden says after deputies corraled the second horse, they were able to identify the owner. That person may face criminal charges.