Here's what this sounds like to me:
1) The featured Google search results box (portrayed as the answer) is autoselected by Google from a third-party website deemed relevant based on the search terms ("date of death")
2) The third-party site initially (since changed) described the death as assassination
3) Google pulled that "assassination" text from the third-party site, and it was placed in the featured answer box
So the assassination text didn't come from search keywords, or directly from Google, it came from a third-pary source that Google selected as relevant based on the search