Presumably they still think he’s (probably) guilty. Victims and their family’s can and often do oppose capital punishment on moral grounds, same as anybody els

Presumably they still think he’s (probably) guilty. Victims and their family’s can and often do oppose capital punishment on moral grounds, same as anybody else. They want him punished but believe that killing him is a moral wrong, or they’re more comfortable with the risk that he’s innocent if he’s in prison with the possibility of being exonerated rather than killed.