SNOHOMISH, Wash. (AP) — The names of four people killed in a small plane crash northeast of Seattle last week were released by medical examiners on Wednesday.

The Snohomish County Medical Examiner lists the following victims:

  • Nathan Precup, 33, of Seattle, Washington
  • Nate Lachendro, 49, of Gig Harbor, Washington
  • Scott Brenneman, 52, of Roy, Washington
  • David Newton, 67, of Wichita, Kansas

According to KING 5, an NBC station based in Seattle, the plane crash occurred on Friday, Nov. 18. The pilots, who all worked for Raisbeck, an aircraft modification company, were on a test flight to collect baseline data before modifying the plane.

The plane’s right wing broke away from the aircraft during the morning flight from Renton, the National Transportation Safety Board said this week. The plane crashed and then burned in a field near Snohomish.

The victims all died of blunt-force injuries, according to the medical examiner’s office.

Raisbeck Engineering of Seattle was having the Cessna 208B test flown before modifying the aircraft, according to a statement from Raisbeck President Hal Chrisman.

He said the aircraft had not yet been modified. The flight crew included two “highly-experienced” test pilots, a flight test director and an instrumentation engineer who were collecting “baseline aircraft performance data,” Chrisman said.

It was unclear who was responsible for which task. Due to the ongoing investigation, the company declined to disclose any further information, the Herald reported.

A preliminary report is expected in the next few weeks. The final report, which would identify the probable cause for the crash, could take up to two years.

To see a video of the plane crash aftermath, click here.