UPDATE: Autopsies were performed Thursday on the bodies of plane crash victims, Robert Groh, 64, and James Quinn, 66, both from the Milwaukee area.
Adair County Coroner Brian Noe told KTVO late Thursday afternoon that preliminary autopsy results indicate the two men died of multiple blunt force trauma caused by the impact of the single-engine plane slamming into the ground.
The plane, making its way back to Wisconsin from Denver, was reportedly attempting to land at Kirksville Regional Airport to refuel.
The aircraft crashed about two-and-a-half miles northeast of the airport as it was making its final approach.
The cause is still under investigation and likely won't be determined for approximately six months.
An online flight tracking website indicates the plane's original destination was the airport in Quincy, Illinois, but the aircraft was diverted and was instead going to land at the Kirksville airport.
Groh was a business owner. He had been in the Denver area to meet with a customer.
Quinn was a flight instructor, who had accompanied Groh on the long flight.
For much of the day Wednesday, federal investigators were on the scene of Tuesday evening's deadly plane crash outside Kirksville.
Teams from the National Transportation Safety Board and the Federal Aviation Administration were supervising as a backhoe gathered up the wreckage of the single-engine plane scattered along Quail Lane about three miles southeast of Kirksville and two-and-a-half miles northeast of Kirksville Regional Airport.
The Piper PA-32 went down shortly after 7 p.m. Tuesday evening as it was making its final approach into the airport at Millard.
The two Wisconsin men onboard were killed.
Their bodies were ejected from the plane when it crashed.
They are identified as James Quinn, 66, of Wauwatosa, and Robert Groh, 64, of Pewaukee.
Quinn was a flight instructor at Wisconsin Aviation.
Groh was president and CEO of GEO-Synthetics of Waukesha, Wis.
A company spokesman said in a statement that Groh and Quinn were flying back from meeting with one of Groh??s customers in the Denver area when the aircraft went down outside Kirksville.
It is believed the two were attempting make a refueling stop at Kirksville Regional.
"Bob is remembered as a man passionate about his business with a big heart for family, friends and employees. He embraced challenging situations, reveling in resolving any problem. He will be missed dearly by all that have had the pleasure to know him," said John O'Connell, CFO and COO of Geo-Synthetics, in a statement Wednesday.
NTSB Senior Air Safety Investigator Pam Sullivan told KTVO at the scene Wednesday that there are three main aspects they examine when trying to determine the cause of a plane crash.
"We look at what we call the man, the machine and the environment,?? said Sullivan. ??So, we'll look at the aircraft, which is the machine, the engine. We'll look at the pilots, their background, their experience, their qualifications and history, and then we look at the environment, which is of course the weather, the airport conditions and so forth. So, we have to put all these pieces together."
There was light rain and patchy fog during the time the plane went down last night, but it's too soon to say if those were a factor in the crash.
Sullivan said the large pieces of the plane will be taken to a secured hangar at Kirksville Regional Airport for examination by federal investigators.
She said it will be approximately six months before the NTSB releases a report regarding the cause of the catastrophe.
Autopsies on Quinn and Groh are scheduled for Thursday in Columbia, Missouri.