Who vs That violation

 In a Washington Post story, no less:

"A pair of siblings — a 6-year-old boy and 16-year-old girl — were among the seven that died, said Warren County Coroner Doug Huskey, adding that he was still working to identify the remaining five victims."

 The rule it violates: 

When you determine whether to use who or that, keep these simple guidelines in mind: Who is always used to refer to people. That is always used when talking about inanimate objects (that computer, that piece of paper…) That can also be used when talking about a class or type of person, such as “that” team.