Christmas tree ignited by child may have sparked deadly Philadelphia fire

Investigators are looking into the possibility that five-year-old playing with a lighter sparked blaze that killed 12

Investigators are looking into the possibility that a five-year-old who was playing with a lighter set a Christmas tree on fire, sparking a conflagration that killed 12 people in a Philadelphia rowhome, officials revealed on Thursday.

The revelation was included in a search warrant application as city and federal investigators sought to determine the cause of the city's deadliest single blaze in more than a century, which took the lives of two sisters, several of their children and others early on Wednesday.