I agree with that interpretation. The 13636 murders contain: 1676 from strangers
5974 with some relation *5986 unknown
Based on the known cases only, I get 22% strangers. More than expected, but it might depend on the region, too (US <--> Europe). Based on that table, we can do even better: We can exclude reasons which are known to be unrelated to the specific case, and persons/relations which are known to be innocent (or non-existent). A bit tricky, as the table is “relation murderer → victim” and not the other direction, but it should be possible.
I agree with that interpretation. The 13636 murders contain:
1676 from strangers 5974 with some relation
*5986 unknown
Based on the known cases only, I get 22% strangers. More than expected, but it might depend on the region, too (US <--> Europe). Based on that table, we can do even better: We can exclude reasons which are known to be unrelated to the specific case, and persons/relations which are known to be innocent (or non-existent). A bit tricky, as the table is “relation murderer → victim” and not the other direction, but it should be possible.