An air ambulance on its way to pick up a patient crashed not long after taking off from Bismarck, North Dakota, killing all three people on board. A military official involved in the response said the plane might have broken up in midair.The twin-engine Bismarck Air Medical airplane took off about 22:30 on Sunday and crashed shortly after in a field about 32km northwest of Bismarck. Air traffic control officials lost contact with the plane about 23:00, county spokesperson Maxine Herr said.CHI St. Alexius Health and Bismarck Air Medical said in a joint statement that the pilot, a paramedic and a registered nurse had been heading to Williston to collect a patient when they were killed. The statement did not provide their names."It is a sad day here for both of our organisations," Kurt Schley, president of CHI St. Alexius Health Bismarck, and Dan Schaefer, operations chief for Bismarck Air Medical and Metro Area Ambulance Operations, said. "We are grieving for the family members of those who were on board."The Morton County Sheriff's Office, Civil Air Patrol and Air Force Rescue Coordination Center based at Tyndall Air Force Base in Florida located the crash scene around 02:00 on Monday using radar and cellphone technology, Herr said.An analysis by the Air Force team indicated the plane might have broken up at about 4300m, and "that corresponded with what they found on the ground," said Civil Air Patrol Lt. Col. Sean Johnson, chief of staff for missions.He said he didn't want to speculate on the cause, which he said could be "any number of things". The National Transportation Safety Board and the Federal Aviation Administration were investigating. FAA records show that the Cessna 441 turboprop was built in 1982. Bismarck Air Medical is listed as the registered owner.National Weather Service meteorologist Jeff Schild said there was no hazardous weather in the area at the time, just light snow, though Johnson said there was the potential for fog or haze.Gov. Doug Burgum issued a statement on Monday on behalf of himself and first lady Kathryn Helgaas Burgum expressing condolences to the families, friends and colleagues of the victims."We are deeply saddened by the news of last night's airplane crash that claimed the lives of the pilot, a paramedic and a registered nurse — individuals who dedicated their lives to saving the lives of others," he said. "We are forever grateful for their service."