Huh.

When I was moving to Hawaii, I looked up the crime statistics to make sure that I didn't get an apartment in Murderton (although Honolulu has a far lower rate compared to other cities of the same size).  Although I can't find it anymore, there was a nice table that split out the crime rates by age here, and I noticed an odd trend.  A large number of murders were committed by someone older than 65, as were a large number of the suicides.

"Elderly victims in murder-suicide identified"