One Of These Crimes Is Not Like The Other

[Fishface]

In the notorious murders of the Grimes and Fritz sisters, there were a lot of parallels. Which one of these commonalities between the two cases is true?

A) The older sister in both cases had a reputation for being "loose"
B) Both sets of sisters went to see an Elvis movie together on the last day of their lives
C) The older sister in both cases was the girlfriend of their killer, and was his real target; the younger sister was just "collateral damage"
D) Both sets of sisters were killed by the same serial killer
E) Both sets of sisters were aged 17 and 13

[Diane in Australia]

B) Both sets of sisters went to see an Elvis movie together on the last day of their lives

[Fishface]

DING DING DING! Correct!