Looking for a See and Avoid NTSB report

I've been reading the book "Aftermath" by the editors of Flying
magazine. The book describes an accident that I'd like more
information on. It was a head-on midair that occurred in VMC between a
Piper Navajo and an Army U-21, just east of Kansas City, Missouri.
There was a single pilot in the Navajo and two pilots in the U-21. All
three were killed. The book does not give a date for when this
occurred. Based on post accident analysis, the book claims that the
Navajo pilot had 24 seconds to see and avoid the U-21, and the U-21
crew had 19 seconds to see and avoid the Navajo. The title of the
chapter in the book is "See and Avoid or Blind Faith?" and was written
by J. Mac McClellan.

I've tried a number of different searches on the NTSB web page and
can't find anything that comes close to this. Anyone know when this
occurred or how I can find the NTSB report on it? Thanks.