Narrative:

#2 aircraft observed through right passenger window. I made a descending right turn. About 5-10 seconds later, #2 aircraft climbed right. I was scanning, but not through that window, just happened to see him.

Google
 

Original NASA ASRS Text

Title: BE35 HAPPENS TO LOOK OUT OF PAX WINDOW TO SEE A BE36 AND MAKE AN EVASIVE MANEUVER WHILE AT CRUISE.

Narrative: #2 ACFT OBSERVED THROUGH R PAX WINDOW. I MADE A DSNDING R TURN. ABOUT 5-10 SECONDS LATER, #2 ACFT CLBED R. I WAS SCANNING, BUT NOT THROUGH THAT WINDOW, JUST HAPPENED TO SEE HIM.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.