SPENCER, Iowa (AP) _ A medical helicopter en route to a hospital to pick up a patient crashed and burned in a soybean field, killing all three people aboard.

The Sioux Valley Hospital chopper went down Thursday night. The cause of the crash was under investigation.

Killed were the pilot, Merton Tiffany, 50, paramedic Shannon Nolte, 30, and nurse Melissa Wittry, 36.

Another helicopter was sent to Spencer Municipal Hospital to pick up the patient, who was suffering chest pains, and take her to the more advanced medical center in Sioux Falls, about 100 miles away.