If anyone's interested, the preliminary crash report has been released:
http://www.bfu-web.de/DE/Publikation...ublicationFile (in german).
According to this report, the Learjet flew in loose formation with the EF when it executed a left-hand turn, in order to follow the fighter. This maneuver turned out to be too tight, the crew having lost sight of the EF. The aircraft then collided with the EF's underbelly, ripping off its fuel tank and heavily damaging the right hand engine. Subsequently, the Learjet disintegrated in mid-air.
The report also includes some pictures, scroll to page 41.