Two mass shootings in California last week that killed dozens of people in public spaces, as well as a third attack days earlier that killed six family members in their home, have again raised questions about whether such violent incidents inspire new ones.
Data on mass public shootings going back to 1966 suggests such attacks are becoming more frequent, said James Densley, co-founder of the Violence Project, a nonprofit research center.
But it’s not yet clear if shootings that come close together in time are intertwined.
“You find even in random simulations, there are times when there’s a cluster and times when there are not,” said James Alan Fox, a criminology professor at Northeastern University who serves on USA TODAY’s Board of Contributors.