My condolences to his friends and family.
A friend of mine was involved in an accident a few years ago during shut down. When he reduced the throttle to 2000 rpm during the cool down period that was sufficient to set off ground resonance. In the ensuing investigation afterwards it was determined that one of the oleo dampers had been rebuilt incorrectly after maintenance.
The other case I know of involved sheer stupidity. A one man band had his aircraft grounded while maintenace was carried out on the oleos. A call came in for him to do a job. Instead of refusing the job he replaced the removed oleos with pieces of wood. The result? Pretty obvious. I suppose almost a contender for a Darwin award.